In reply to a post by candlerb:

In reply to a post by lo22:

One question, do all ISPs allow for third party routers?

No, but most do, including almost all Openreach-based providers. It's mainly the altnets who provide locked-down fibre routers.

Some of the smaller ISPs (again including Cerberus, Aquiss) don't supply a router as standard anyway, so the default situation is to provide your own.

The only thing to beware of is if you use your telephone number. Providers often lock down their telephony connection to their own router, in particular BT. So if you have BT with digital voice, you *must* use their router, or else lose access to the voice service.