I've finally got FTTP up, and after a router reboot, have it all running at a nice speed. Overall good, but I thought I'd point out that the Technicolor router I was supplied for the FTTP trial was setup so that its FTP server was facing the Internet by default - not good, especially if you've changed the admin password to something more trivial than the factory supplied one

This was easily seen by checking with an online service (e.g.
https://www.grc.com/x/ne.dll?bh0bkyd2) or nmap from a machine on the Internet.
Finding and "unassigning" the FTP application via the router config webpages fixes that at least, but it's a surprising default config.