Hi,
Nothing else I can do. : -(
I don't know any specific details for Norfolk, but IMHO there are other options.
Firstly, there are other operators, including one actually owned by BT, that will use the same Infrastructure. I was with that other operator for a number of years and found their (UK based) technical support quite good.
But then we moved to a location which was clearly going to have a very poor ADSL broadband connection (nearly all the neighbours appear to be on "Cable TV " or Fibre) with a "predicted" ADSL speed of around 3 Mb/sec. Also, with no active telephone line, there was going to be a potentially high installation cost so we looked at "Mobile Broadband". We started with a "Portable" Router and 20 GB/month package, but have now graduated to an Unlimited Contract (24 months) still for less than £20pm (their current offer appears to be "£15pm) with no "introductory offers", so should only increase by the RPI after then. The "free" (included) Router has an Ethernet socket but also supports 50 WiFi channels on both 2.4 and 5GHz bands (and external antenna sockets if needed), etc.. The "headline" speed of the Router is 300 Mbits/s, but the realistic speed I've seen has been up to 40 Mbits/sec. Subjectively, the 5GHz WiFi (not to be confused with "5G" mobile coverage) is faster and has greater range than 2.4GHz, probably because the radio band is less congested (at present). The upload speed is usually much the same as the download speed. A "fixed" internet address is not available, but "No-IP" is free and supported by the (Home) Router.
No installation costs and the Router will probably be delivered "next day". You might want to install it upstairs and/or at a window (on the cell transmitter side) but ours is just next to the TV. Also a "WiFi Extender" (<£20 plugged into a mains socket) gives another (remote) Ethernet socket, 5GHz WiFi (transcoded if necessary), and greater coverage. You can check out the speed you may get by running "Speed Test" on a mobile (smart-) phone (which can also probably be configured as a temporary "tethered" Hub for trials). Tip: not only is my particular operator the cheapest, but you can get a further discount as an "existing customer" - which needs only to be one of their mobile phone numbers (e.g. a PAYG SIM).
Not particularly relevant at the moment, but it also allows you to take your own equivalent of "free WiFi" to many locations in the UK and around 70 other countries. Also, if you're uncertain, then both the providers I've mentioned do offer "monthly" contracts, but at around 50% higher price and of course no "free"/included hardware.
Of course there are a few "Cons", in addition to the "All your Eggs in One Basket" aspect of mobile broadband. There is no "guaranteed" speed now (or particularly for the future), sometimes it can be slow and it might not be the best solution if you primarily use catch-up TV or video streaming. At my previous address there were two commuter railway lines (and stations) between me and the cell transmitter and in the "morning rush hour" (pre Covid) the mobile broadband virtually stopped. Now, our (mobile) broadband sometimes seems "slow" and a Speed Test can occasionally be below 1 Mb/sec. However, a reboot of the Router (directly via the Admin UI) nearly always gets it back at least to double figures within a minute; it might be a bug in the Router, but I suspect the mobile connection becomes "stale" after a number of days. And I do have to admit to having wasted some hours in the provider's shops, and on the phone to their unintelligible "Customer Support" somewhere in Asia.
Cheers, Alan.