As someone who has worked building stud partitions and dabbing plasterboards to solid walls, I can say that you will have a difficult job if not impossible running a cable behind the plasterboard!
If the wall is a metal stud partition it is easy to run the cable as metal stud partitions normally do not have horizontal fire breaks but will have insulation blanket. If the wall is a timber stud partition it is going to be almost but not necessarily impossible to run the cable as it will by law have horizontal braces as fire breaks plus insulation blanket! I say not impossible as there are tools to drill through the horizontal timber braces, but the price of the tools will probably give you a heart attack!
If the plasterboards have been dubbed on to a solid wall you will be extremely lucky if the adhesive dubs are all in a vertical line!
You have quite a job in your hands, and I wish you good luck with trying to feed a cable behind the plasterboard!

I�m assuming you are not from the UK with your descriptions. The horizontal braces are commonly called noggins, and are used in the UK for support to stop twisting rather than fire proofing. I am not sure what you mean by fire insulation as this is something existing houses in England do not usually have / common at all, they are usually hollow cavity�s. Businesses tend to have better quality fire boarding plasterboard with intumescent sealant on joints and if lucky putty or similar in the dry lining boxes. Businesses also tend to be metal framed.

To get through the noggin worst case you would simply make a small hole below it and drill through it, worst case you�d need a small access hole above too. This is then patched up and painted. With a lot of UK sockets in newish 2000 ish houses being quite high up you can sometimes use long drill bits, or adapter with drill bits on.

With regard to Dot and dab, routing cables is a regular job for most electricians. It�s not impossible at all just because the dabs are out of line. The rods or fish wire devices you can get will twist around them (although it takes time and patience) it�s got to be one of the main advantages of that kind of wall. I�m not an electrician but I�ve found it relatively simple to run cables via this type of wall. Worst case if you can�t get round the dab is cut a hole and chisel a route through and fill.

The easiest solution here is to just use the existing wire using some ethernet extenders or moca or powerline technology. Running the wires sounds like it will be a really tough job.

My only advice would be don't use Cat 6.

I was planning on using Cat 6 for mega future proofing. But after fitting a few connectors to Cat 6 cable I decided it was far too much of a pain in the behind and went back to using nice easy Cat 5

I've come to the conclusion that the only place I'm likely to actually ever "need" Cat 6 is between my server and my main machine, which are connected to the same switch in the same room...

Depends if you are doing it properly then you are punching down the cable whether it be Cat5e, Cat6 or Cat6A to either wall plates (or modules for a wall plate) and a patch panel, it's very little difference to be honest. I did my house in Cat6a because it was free and my sisters in Cat6. My brother went for Cat5e and it is all much of a muchness to be honest. If you are crimping plugs on the end of solid core all over then you are doing it wrong. I have a handful for ceiling mounted access points and the like but it is little different from Cat5e in my experience, and you need specialist plugs anyway.

Sure terminating it properly so it will support 10GbE is harder due to the very short amount of untwisting allowed. However if there is plenty spare you can re-terminate properly when you need the 10GbE at some future date. Same goes for the RJ45 plugs, you can just use Cat5e rated ones for now if you want. It's running the cable that is the real hard work, so even if you need to get someone in at a later date to terminate properly and test it is much cheaper to run the right cable now.

Given that Cat5e does not support 10GbE under any conditions (you might get it to work be it is completely unsupported) I would always recommend going for at least Cat6 if your runs are going to be short (aka under ~40m which is usually the case in a home environment), or Cat6a otherwise.

A top tip is to buy the LZOH versions because they are usually purple which means when you have your head under the floor at some later date you can immediately identify the network cables from the other stuff.

Final note don't waste your time and money with Cat7. Firstly it is not required for any supported standard. Second unless you are using the GG45 plugs with equipment that can support them (which is virtually nothing) then you are making things worse than if you just used Cat6a cable.

I'm lucky that I live somewhere with zero* neighbouring wifi signals. So I don't need to do it properly

All my cable runs end in hidden away loft spaces, mostly connecting to wifi APs, so just terminating connectors on the runs suits me. I very quickly came to the conclusion that terminating Cat6 connectors was not worth my time and frustration.

I'm not dropping cable into living spaces (except one away in the corner of my office), as wifi works well for me, so I don't need wall plates and the like.

I know this isn't typical for most people (with neighbours), where if you want something reliable wifi isn't an option.

* nearest neighbour is >50 metres away, can't see their wifi network even when standing outside

In reply to a post by andynormancx:

I'm lucky that I live somewhere with zero* neighbouring wifi signals.

<snip>

* nearest neighbour is >50 metres away, can't see their wifi network even when standing outside

Zero? You need a better antenna

Sometimes it's surprising just how far Wi-Fi signals go. Right now, the place I'm at has an outdoor access point that recently picked up a neighbouring Wi-Fi signal originating at least 10.76km away, and likely a bit further. The culprit; this - running a Pepwave system with a signal strength where I am of 9.9% (-86 dBm)

I expect if one my Unifi APs was mounted outside it might see one of the neighbours, but they all have at least one brick wall in the way (and >50 metres distance)...

I means I get to occupy the entire 2.4GHz wifi spectrum with my 3 APs

In reply to a post by andynormancx:

I expect if one my Unifi APs was mounted outside it might see one of the neighbours, but they all have at least one brick wall in the way (and >50 metres distance)...

I means I get to occupy the entire 2.4GHz wifi spectrum with my 3 APs

Luxury indeed

I've got another Unifi installation later this week with four internal access points and one external. The house is a bit awkward as it's two standalone buildings that have recently been joined together - a house and a separate garage. This means that in places there are two external walls now inside between one room and the adjacent room. It's not ideal for getting Wi-Fi around.

With a bit of luck If there's a bl**dy miracle, SFR will be installing FTTP on Thursday.