To allay any more worries for the OP, 36 months contract only applies to Fibre on Demand, not native FTTP which is what the OP us trying to get.

I for one can understand your frustration, As I have had ongoing issues with Virgin media`s 120Mbit connection not working as it should and I put up with it for 2 years as fiber was not in my area. All I could get was A 120Mbit line running at 20Mbit or ADSL running at 1Mbit. So I chose the Virgin line, It upset me to stay with them, But I did not cut off my nose off ,blah blah. LOL. Now 2 years on virgin are still rubbish and my area has FTTC with VDSL2. I have now dropped Virgin and enjoy BT`s 80/20 service at 76/19.
If they are going to fit FTTP,(I.e fiber into your home, Then, My advise to you would be put up and shut up.
This line will give you what ever speed you buy from your ISP (as long as the exchange is running ok). I,e 40/10, 80/20, 300/30 will all run at full rate.
For me to get FTTP in my home it will cost me a 1.5K fitting charge.
If you still want to cancel then they have no hold over you and if they continue to tell you so then ask them for a "DEAD LOCK LETTER". you then send this to CISAS and they decide the decision.
My advice to you would be to put up with it and let them fit the fiber. In ten years time that fiber could be giving you over 1 Gbit up and down whilst FTTC is stuck on 200Mbit.

Whilst this is potentially covered by sales acts, BT have done pre-work installing the fibre that has incurred costs for them and so if the contract is cancelled without agreement then they may try to recover the costs of installing the fibre. This could end in a nasty court case either brought by BT to recover costs or brought by the user to contest the contract cancellation charges that BT would potentially try to make.

While it is being a PITA, I to would still go ahead with the installation, the rewards will out way the grief which will soon be forgotten once connected.

In reply to a post by ian72:

Whilst this is potentially covered by sales acts, BT have done pre-work installing the fibre that has incurred costs for them and so if the contract is cancelled without agreement then they may try to recover the costs of installing the fibre. This could end in a nasty court case either brought by BT to recover costs or brought by the user to contest the contract cancellation charges that BT would potentially try to make.

yeah legal advice required, my gut feeling tho is he is ok but is a chance may be have 'some' liability covering work already done. but in the service market I have seen contracts that have a stated a no point of return prior to services going live although I never looked into if they were legal terms.

In reply to a post by R0NSKI:

While it is being a PITA, I to would still go ahead with the installation, the rewards will out way the grief which will soon be forgotten once connected.

Agreed - the project to get FTTP to our village was estimated at 15 months; it overran by 22 months; evasion and excuses at every turn from BT. Even now not everyone can get it. But if the only option is to plough on with a slow adsl connection then you really have no choice (assuming Virgin is not available). Keep plugging away - it will be worth it, believe me!

Please keep us posted on how things go..

I for one hope that they can get your FTTP installed