In reply to a post by squarecrumpets:

How are the ONTs mounted to the wall? drill and wall plug? adhesive?

Well, if 'Kowboy Communication' are involved, the wall will be peppered with holes which are filled with red plasiplugs, some of which might be suitable to attach the ONT.

In my case it's a separate ONT (Adtran SDX611), which I have then connected to my own router with cat 6.

My recently instralled ONT is fixed to the wall adjacent to the old phone socket. For my installation, that was the best place. My router was already nearby.

So in my case this is not materially different to what went before.

Before: Router via DSL cable to splitter to phone socket
After: Router via Ethernet cable to (fixed) ONT Ethernet port.
The only extra: a mains outlet to power the ONT (and it so happens, that was already there).