Most of the big players are 18/24 month contracts. You might have a bit of a struggle finding a suitable no contract, or rolling contract deal on fibre. There are also 4G/5G options available from 3, EE etc which offer monthly deals.
ach, I had a better ping to the servers piglet on your type of connection than my current fttp. Think it's something to do with the cab routing and location as opposed to router. Admittedly I have noticed the ISP routers use a different faster set of DNS servers as opposed to non isp ones. I think you can redefine those if I can get them out of the ISP router... in theory. (My speed is slightly higher with isp router). Make sure you've got a BT socket with a mk4 vdsl plate on your wall, also make sure it's the master socket you have connected your router too, you'd be amazed the speed boost you can get out of a copper connection
Fibre To The Premises is much more stable than ADSL/broadband). Be careful though BT used to offer fibre 1 which isn't fttp, it's only Fibre To The Cabinet (big green BT boxes you see on street corners).
I'm from London hellfire Whichever gives you best speeds for price. Personally I prefer dealing with BT/EE/Plusnet for customer service (mainly UK call centres)