Zen is on my list.
Think it was idnet and uno that are 'dormant' companies
I can assure you that both uno and IDNet are very active at the moment. I just had a new FTTP service on BT Wholesale go live at my new house in Sheffield on their 1000/115 package and am easily getting over 700Mbps using WiFi 6 2x2 80MHz. I have yet to test with a wired connection (laptop issues) but will be doing so tonight. I have found IDNet have very good support via email if you have questions and their availability checker is
extremely detailed. When I used it, it was able to list everything including the ONT serial number!
I can also highly recommend Zen as I was a customer for many years, though their customer service has grown somewhat less technically inclined since I joined them which is why I am using alternate providers now. My grandparents had a service with uno for a short time and it proved reliable with good technical support, though they also use TalkTalk Business on some of their packages so it may prove to be problematic.
If you have any questions regarding the installation of Openreach FTTP let me know, this is the second property I have been at with FTTP.