It doesn't sound ideal, but in fact you've picked a good area.
https://www.geograph.org.uk/browse.php?p=706831
https://www.geograph.org.uk/browse.php?p=707731

Thought I'd post this for others that may come after.
As Colin says the coastal path north from Crawton soon becomes absent and you're in the field margin. The local farmers aren't on any 'field margin' compensation payment so they are non existent , and I can only admire the skill involved to drill so close the field boundary. None the less a way is possible without destroying precious oats/barley, but not one to do in shorts. Since you stick close to the actual cliff top your distance estimates will be off a fair bit.