Agreed, ref the Exeter and Wellington waters, but you might be a tad disappointed as far as Watchet is concerned. The Watchet 'beach' has what is laughingly described as a boating pool - only it's full of rocks, gung, johnnies, weed and everything apart from water. They used to be pretty cool about sailing your models in the harbour actual - especially when they have their annual carnival weekend, but all that has changed now - they only permit the harbour for full-sized mooring. Plus it's smelly there; they have a terrible problem with their sewage/drainage systems.
The River Tone at Taunton is sometimes used by a few die-hard modellers, as too the local waters at Tiverton.
As a point of interest, although I have never been on your side of the border, they tell me that Scotland is a magical place. Why would your good lady want to give all that up in exchange for this dead-end dump?