There are nude capsites in Devon and some lovely beaches to go naked. Blackpool sands is but one
I dont believe Blackpool Sands in Devon has any naturist activity. Slapton Sands a few miles down the coast is most definitely naturist, but not Blackpool Sands.
Holkham tends to get very busy in the summer and parking on Lady Anne's Drive is expensive. There are other options in Norfolk and Winterton Dunes are worth exploring. You can get to the naturist area from either Winterton or Horsey. A bit of a trek but worth it. The dunes are less busy than Holkham and I've found it to be a friendly community when there.
Well just had 3 weeks in Devon. Slapton sands was lovely, crystal clear water and not too busy. The only negative is the shingle is really hard to walk on. Sand shoes are a must have. We had been intending stopping at Manor Farm campsite, part naturist part textile but it was very run down and we decided not to stay there. Moved up to Budleigh Salterton which has more facilities as it's right near the town. The beach is larger pebbles which are easier to walk on but not very comfy to lay on. The sea wasn't as clear as it's coloured by the local rock.
Slapton was definitely nicer but Studland and Morfa Dyffryn are nicer.