My FTTP cable is inside a blue plastic water pipe for protection. It no doubt resists pressure from any stones that are in the ground and is probably harder to put a spade through. The piping is the wrong colour but easy to buy. Gigaclear use a black plastic pipe that is easy to bend because it does not have a uniform thickness.

The Openreach Developers Guide page 24 does show cable TV and Communications in a green pipe 250-350mm deep, as well as Telecommunications 350mm deep in a purple pipe.

If your neighborus have the same problem it might be worth while trying to buy some piping of the right colour.

I had originally thought about putting it inside water pipe but as it is a run of 65 metres I don't know if it would be possible to push it through that length of pipe.

I happened to know that I could push foam filled TV coax down about 20m of straight pipe. Using this technique I installed string in the pipe. There is a joint in the pipe which because of the inserts is difficult to pull a cable past without opening the joint.

Another technique is to use a vacuum cleaner to suck something like a cotton ball attached to a thread down the pipe.

This would be a run of 65m and not straight or level unfortunately.

Get a decent high powered vacuum cleaner,form a ball of fabric and tie a piece of fine fishing line to it. Seal the vacuum hose around one end, switch on, introduce the fabric ball at the end and gradually let out the line. When it is through, tie teh line to the fibre and pull it through whilst someone else feeds it in.

If you fail to do it in one, cut the pipe into three sections and then join using plenty of self amalgamating tape.

Lay the pipe out straight perhaps using bricks to hold it down and then get the string in before you install it in the trench.

In reply to a post by andyfr:

Highlands

...Or drag the pipe to somewhere nearby with a pretty harsh 65m slope, attach a small weight to your draw-rope, then drop it down until it comes out of the other end for someone to catch?

I think at one point some aircraft manufacturers used ferrets to do the cable runs, didn't they? Well, draw-rope runs.

Or proper duct. For example
https://www.drainagepipe.co.uk/products/bt-duct/

Adds up over 65 metres, though.

Do you have to get the fibre cable into the duct yourself? Or just leave a draw rope for BT to pull it through with?

Openreach is saying no need for ducting as its armoured and can be direct buried...

BT didn't mention that I needed a duct, they just said that I had to dig a trench up to the house and they would supply the cable. I wasn't thinking about putting any ducting in as I thought it would be okay if it was deep enough and covered with soft sand.

How thick is the cable?