I elected to move to yayzi from Vodafone and had cityfibre out on Tuesday, who did not a lot! What they should done (but I wasn’t aware at the time!!) was upgrade the ONT to support multi-gig service.
Besides that they never closed the job. Queue lots if support emails and WhatsApp’s with the team as both my wife and I are home workers, and to top it off mobile data reception is poor where we are so no hotspotting 
Finally got sorted on Friday when CF came out and upgraded the ONT! Service on straight away!!
Thanks to Liam, Chris and the team for all your help and support with chasing up CF.