Again the use of the word FTTC is slightly wrong and would cause confusion, as you would have an ISP saying you cannot order a FTTC service on a FTTP line, which is correct.
What you can order is a GEA-FTTP product that is speed and price matched to the GEA-FTTC products.
For FTTP at present as a consumer BT Retail and PlusNet are the only two to offer the 40 and 80 speed products to people on FTTP lines.
The majority of providers who sell the 40 and 80 Meg products currently only sell them in areas where FTTC is available, due to their desire to keep things as simple as possible for sales staff.
I believe once you enter your details on the BT retail website it should open up and show the full range of FTTP options.