UPDATE 2
All installed and mostly* working!
Took about 45 minutes.
No new holes drilled - pulled the copper out, and put the fibre through that hole.
Connected router (A&A supplied Technicolor DGA4135) and it took a bit of back and for with A&A to get it up and running.
Ordered the 1000/115, and getting 650/110 via ethernet to the router.
WiFi wasn't working, with devices just dropping the connection after 2-3 seconds, and then trying to reconnect. But I have switched off the router wifi anyway, and connected it to my existing Mesh (BT WholeHome Wifi Mesh AC2600) and getting 450-500 all over my house, so I think on balance that's pretty good!
*The one thing that isn't working is the VOIP.
I have posted my query in the VOIP forum, to ask for help.
https://forums.thinkbroadband.com/voip/f/4771363-hel...
But i wish the router came with detailed instructions and advice on what all the settings mean, and how to configure for VOIP.
A&A have some support pages, but they're quite complicated for a noobie.