You can use the search facility on here, but would have to contact the site to find out if dogs are allowed in the clubhouse. We don't use that type of site, so someone else may be able to advise more.
As well is two words!
How does a sage know everything about everything? or does he? or does he just think he does?
Remember, if you buy something you bought it, not brought it.
Queensberry (near Annan, SW Scotland) allows dogs into a specific area of the cafe bar.
But - by “campsite”, are you in a tent or a tourer? This place is for tourers not tents, but the clubhouse only exists because there are statics too, to supply the volume of trade needed to keep a clubhouse viable. Lilliardsedge (near Melrose) is more usual, in my experience: dogs only outside the clubhouse on the deck.
Otherwise, I can think of sites that are in walking distance of a pub that welcome well-behaved dogs (“3 barks & you're out”) - Kippford site is in walking distance of The Anchor which allows dogs inside. Melrose CAMC & Moffat CCC ditto.
Eye Kettleby Lakes in Melton Mowbray have a specific area of the bar where dogs are allowed. Bay View Caravan Site in Bolton-le-Sands, Lancashire also have a specific dog friendly room off the main bar with about a dozen tables.