Best beach?

I dont know about closest but the best one around here is Studland, you will need a pass to ride, contact the National trust at Studland Dorset!
 
Brean berrow or Weston would probably be easiest as on motorway most of the way. if you search for riding and those beach names you will see when you are allowed to ridea on them and where to park
 
Perranporth, 3.5 miles of sand, and a mile between the sea and the dunes when the tide is out too!

Marazion is good too, also over 3 miles when the tide is out.
 
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