There’s no reason your Sonos shouldn’t connect to the BT router. Have you ensured you have separated your router’s frequencies so you have both 2.4ghz and 5ghz wifi available when you search for wifi, rather than just the one combined wifi name?

Thanks for your reply, yes I've done everything possible including disabling 5ghz but it just will not work for me. I've gone in to the router settings and on devices connected the sonos shows as connected to it but the sonos app will not show the speakers.  When I reset the speakers the app finds them no problem it then plays a test tone but the issue is after I put the password in for my router, it says speakers added but may not show in your system. But they don't show. The sky router I came from had no problems at all with my gear so I don't know what else to do. 

As they are connected to the router (that is a very good sign), do the speakers show up on the desktop app for Windows or Mac available from the Sonos website? 
These desktop apps can often solve issues the phone versions can’t.

I’m pretty sure lots of people have their systems running OK with the BT smart hubs - I have the Plusnet equivalent and it works without problem (with app version 16.1). I would be cautious about jumping to a new router until you know for sure that your problems are not due to the now-notorious new app.

By the way, if you can change your WiFi name and password back to what it was on the Sky router, that may well help. The Sonos app seems to hate a change of network, so maybe fool it into thinking you’ve not changed network. You might need to reconnect your speakers again I’m afraid but it could be the solution. 

After you add the speakers, reset the controller.

Thanks for the suggestions guy appreciated. I have managed to get my one sl's and my sub mini playing and all working together in a room named living room, I also tried adding my beam 2 to the same room but the app has created a separate room for some reason even though I instructed it to join with the others. How can I resolve this and get it working as a 5.1? Thank you. 

You must build a surround Room starting with the soundbar.

Remove SUB from the pair, then unpair the ONE SL’s. Now you can add the SL’s as surrounds to the soundbar and add the SUB.

The sub and surrounds connect to the Beam via the Beam’s own ‘private’ 5ghz wifi, to bond them all (for 5.1 and Atmos) and ensure they stay in sync. So you need to start from the Beam.

Starting with the Beam settings, go to Connect Sub to add the sub, and Connect Surrounds to add the One SLs.

Thanks fellas I'll give that a try  

Once the Sub and One SLs connect to the Beam, you should then see only one “room”. 

Reset my one sl's and set them up again to try and add to my living room with the beam 2 and sub mini but it's created another room with them as a stereo pair. When I go in to the living room system and try adding the I get this message all the time. 

You can’t add a stereo paired set of speakers as surrounds.  Separate the pair so they are 2 separate rooms, and then add them as surrounds.

I've done that and now I've got this ‍♂️ this is taking some graft isn't it

I've just force stopped the app cleared cache reloaded the app and bingo it's added them to my system thanks for all the help and time guys I appreciate it all. 

So you should just have one ‘room’ now, with all three speakers bonded? 

Enjoy the surround sound!

(Glad you didn’t buy a new router!)

Yes I've got all my speakers set up as one system now in living room.  Definitely glad I didn't waste my money on a new router. Thanks