anyone found a family-friendly hotel with facilities for a larger family?

[Notmyidea]

we're looking into taking my cousin's children away with us next summer while his wife gets over expected spd in late pregnancy and c-section number 3. I'd like to find somewhere in the South West, or Wales that's very bucket-and-spade friendly, but fully catered with baby listening, (I'll have a 6-8 week-old myself and will fancy a bit of pampering! As will dd who will have just survived her sats) and can take two adults and 5 kids aged between 12 and newborn. Any ideas or am I going to have to do self-catering?
I figured the larger-families board would know!