If you have checked your phone number
in the Infinity checker, then you may get away with their 40GB allowance version, but I have my doubts. Your safest bet would be the unlimited one. It might be worth asking BT what happens if you go for the 40GB allowance one and it isn't enough.
There are many other ISPs that can supply FTTC, see my page
and the link on that to Orly/Yarwell's summary speadsheet of them. There will be lots of other players by now but little publicised. For any of these to be on your shortlist you would need to be able to specify your requirements very precisely in terms of the usage pattern and volumes. As you say, I don't think you can possibly do that as you haven't got broadband at the moment.
Also read the parent page of the one I just linked to. It tells you more about FTTC installations. In the case of your master socket the engineer would completely replace it with a modern one.
The FTTC modem has to be by the master socket, or at the end of a Data Extension Cable
that the engineer can fit. Up to 30 meters away is the standard provision. Some engineers can be persuaded by tea/coffee and biscuits to move the master socket if the current location would be very inconvenient. The best ones don't even need the drink and biscuits, but no doubt many welcome them
VM Cable may or may not be OK. It seems to have an extremely wide variation in the "Customer Experience", depending on the particular location. It would not use your existing phone line.
Don't forget if you go for Infinity then by ordering online through TopCashBack or Quidco you stand a fair chance of a few pounds back.
My broadband basic info/help site - www.robertos.me.uk
My domains,website and mail hosting - Tsohost
. Internet connection -
Plusnet Value Fibre.
"Where talent is a dwarf, self-esteem is a giant."
- Jean-Antoine Petit-Senn.