As my nearest bit of sea is a 173 mile round trip (& that's the Wash, so add on a few more miles for actual sea

) I have to make do with reservoirs
Cransley
Thorpe Malsor
I think I've finished Northamptonshire now

and have also been to:
Leics – Eyebrook, Saddington, Thornton
N’hants (completed) – Barby, Boddington, Cransley, Daventry, Drayton, Hollowell, Naseby, Pitsford, Ravensthorpe, Stanford, Sulby, Sywell, Thorpe Malsor, Welford.
Oxon – Clattercote
Warks – Brownsover, Draycote, Earlswood Lakes, Napton, Oldbury, Stockton, Wormleighton