Sorry! I live in the south of England and it's surprising how few people know about the difference in term dates. We visit in the second half of Aug every year but stay wirh family so haven't got any suggestions I'm afraid.
We're just back from a longish Easter Break in Maybole in Ayrshire; loads to do and see, we are NTS members so lots of free entry to Culzean Castle, Robert Burns places etc. We haven't been to that area of Scotland much and were pleasantly surprised!
Theres lots of BnBs, static caravans, and pod camps in that area (although we are hardened touring caravanners).
Great rail links to Glasgow for some time at museum of transport.
Lots of accessible beaches, we just looked at them as it was freezing!