Re: I would make the move...
This is a quick and dirty pull of the ISPs Open Reach list as FTTP sellers. It isnt complete as O know of at least a dozen others; but then OR always have been 2-3 years late in updating lists of anything.
Andrews & Arnold Ltd
www.aa.net.uk
BT
www.bt.com
Ceberus Networks
Cerberus Networks
www.cerberusnetworks.co.uk
Spectrum Internet
Spectrum Internet
spectruminternet.com
Structured Communications
Structured Communications
www.structuredcommunications.co.uk
Syscomm
Syscomm
www.syscomm.co.uk
Zen
www.zen.co.uk
The following is a list of ISPs offering 100+ Mbps, so not all fibre, there are a few cable company offerings and wifi mesh services included.
https://www.ispreview.co.uk/isp_list/ISP_List_Ultrafast_Broadband.php
Once again, this list is already out of date; I know of at least a dozen other ISPs offering FTTP.
Quite why people seem to think ZEN is the only alternative to BT, I dont know. When I was thinking of giving them a try 4 years ago, I could never get a response via phone, contact form or email from them. Even their own ISPR rep was getting frustrated with them.