[MovedGoalPosts]

You have a specialised requirement. The lack of reply probably indicates that nobody really knows.

You know what you might get from Virgin Media, if you've been using that service to date. But that can change as other users are connected (or leave) in your area.

Anything else at a domestic level (ruling out the leased line, etc) will use the BT phone line systems, whether that be the outdated ADSL, or now FTTC - Fibre to Cabinet - aka BT Infinity). Some areas may have the extortionately priced FTTP (Fibre to Premises) It seems irrelevant whether you get BT, Sky, Talk Talk or another provider. Both ADSL and FTTC But whatever is on offer can depend on the condition of that last copper wire between the cabinet and your home, and there can be some effect on distances.

Another variable is contention. i.e. all domestic services will share connectivity at the exchange, cabinet or whatever. This applies just as much to BT or Cable type services. For most people that isn't a problem since few of us saturate our connections simultaneously. And the ISPs also have some Quality of Service measures to prioritise some traffic types. The effects of contention will vary from area to area, and even time of day.

And then of course there will be the effects of your own internal connectivity, presumably ethernet cable, and whether you use the ISP supplied router, or your own.