In answer to my own question and having read the detail of the replies below (thank you everyone), it seems that at 1.6km I am much better off on VDSL2. FTTC has just been enabled on my cabinet and I was fortunate to have one of the first installs on Monday this week. My initial sync at 1.6Km from the cabinet was 20Mbit/s (up from 1.3Mbit/s when using ADSL2+ to the exchange!), but as I write, my connection speed has reduced to 17.5Mbit/s. I think this might be due to interference from other lines that have gone live this week.

Since my VDSL2 speed of 17.5Mbit/s is better than the 12Mbit limit that would be applied to an ADSL2+ connection from the cabinet, I am clearly better off on VDSL2. It seems that the BT testing guidenlines show that the sweet spot for ADLS2+ connectivity from the cabinet will be 2 - 3 km from the cabinet.

I would be really interested to see other people's connection speed vs. distance to the cabinet. Most of the statistics I can find on the Internet seem to be old, so I'm wondering whether the performance I am seeing is good or not given the line length to the cabinet.

I'm approx 9km from the exchange and have 0.5mb on ADSL2. My fibre cabinet is approx 2km away but this is too far to be offered FTTC despite my neighbour being given an estimate of 16mb, so I am exactly the person this is aimed at. I would say the 12mb limit is to prevent people sticking on the ADSL product which I would imagine will be cheaper as per the option 3 with fibre product from BT, rather than go for fibre, especially if they are within 5 or so mb of a more expensive Infinity product.

"My fibre cabinet is approx 2km away but this is too far to be offered FTTC "

Err really? FTTC works at that distance though I appreciate it may not be the best technology for speed.

Err really? FTTC works at that distance though I appreciate it may not be the best technology for speed.

Err Really? How does 4.8Mbps on Fibre grab you? Oh, same price as 78Mbps, of course..................

Why is 4.8 Mbps the same price as 78 Mbps?

When I looked the 40/2 product can be had for £13.50 versus £15 for 40/20 or £30 for the 80/20.

FTTC does have some element of speed/performance pricing involved.

Yes, my mistake - same price as 40Mbps - much more acceptable.................

Which might drop another £4 to £5 a month if TalkTalk gets it way anyway.

As things stand the TalkTalk 40 Meg service is cheaper than some other providers ADSL services.

Err Really? How does 4.8Mbps on Fibre grab you? Oh, same price as 78Mbps, of course..................

The cost to the service provider is essentially the same regardless of your speed, all the more so if you were to download and upload the same amount albeit at a considerably slower rate.

Well i'm getting 0.5mb on an up to 24mb product so the cost thing isn't really an issue for me. If I could get 2mb on a fibre product i'd take it, but because it doesn't show on the address checker (with talktalk so no number check) I just get stonewalled by sales.
So frustrating that I know my line can be quicker but I can't get anyone to sell me anything! I'm even considering BET at this stage!

This scheme would be great on our exchange, it is a Market1 exchange and never had 21CN enabled so we are all on ADSL1 MaxDSL connections still, despite paying more per month.

The two new cabinets have been installed and BTO are currently running new Fibre to these cabinets, it should go live in December, it should have gone live this month but a duct was blocked and a road needs closing for it to be cleared and then have the Fibre blown.

The two cabinets are large enough to handle all the lines in the area, so the exchange itself could become defunct and the ANFP problems could be avoided by moving the ADLS2+ connection to the cabinet, would be great to trial this new scheme if BT are looking for locations.