@LucyBee I presume with virgin you had the option to change your route to bridge mode and the deco provided the dhcp etc. right?

Even if your new provider doesn't let you switch them to bridge mode, the deco will work to provide AP functions, albeit it might not say so.

The WiFi is probably unstable as the SKY router and deco are broadcasting the same SSID but with different network addresses as the Deco will try to create its own NAT network behind the main router.

There is a way to make the deco work as an AP on your normal SKY network, i cant remember what i did to make it work (not helpful i know) i'll play with mine to confirm.

  @Ian_D 

thanks for the reply,

yes I had the virgin router in modem and then used the x20 as router. 
Currently using the x20 in access points as SKY won't let you out router into modem mode. 
move just turned off the sky wifi completely so will see if that helps 

But may switch provider as Sky monumentally unhelpful and just trying to sell me broadband boosters!

  @LucyBee 

Plusnet and BT FTTP will work with the X20 as they use PPPoE as the connection type so you can connect the X20 directly to the ONT where the fibre comes into your property.

  @LucyBee ahh yeah, SKY support, or the lack of :)

Thats a real pain if you cant switch to bridge mode then. Maybe you're right, new provider time that will let you.