Don't walk from Perranporth, you can drive through the campsite halfway down the hill and park cheaply or park the other sides of the dunes and walk on the OS footpaths through the dunes. Do not lay in the dunes as they do have the Lifeguards come along on there 4x4 buggy and will ask you to leave if you are in the dunes. this was last year so interested if they do it still.

If you go through the village / hamlet of Rose towards the sea at a T junction you will find a parking layby. Can walk from there fairly long walk through the dunes to the sea (heading slightly left at first and definitely left if you hit the fence to get round it) once at the sea turn right and walk up the to the very far end where there are low cliffs. That's the recognised naturist area. I was there a couple of years ago and there was no issue with the life guards in that area, they just rolled up and collected their sign at the end of the day and didn't bat an eyelid.
Hope you enjoy.

I cant see what authority lifeguards have weather one is clothed or not, surely if you are not trespassing then being clothed or not is irrelevant? Does anyone have more suggestions for parking closer to the naturist end of the beach, happy to pay to avoid a long walk

The lifeguards that encountered me weren't that fussed at me being naked just wether there were people in the dunes. That is the problem beach ok dunes not. I think this must be the civil working with the military who own the dunes, it was the military that wanted it stopped due to to the training of cadets on the area of the dunes.

I can see the sense in not antagonising the land owners behind the beach as I'm sure they could make access difficult it does look a long walk up from perranporth otherwise .

there is a "Haven" site at the top of the hill, just up from Perranporth village.
you used to be able to pay to park there and just a short walk down the dunes to the beach.
I'm sure reception there would be able to advise if this is still possible

Which ever way you go you have a walk like most naturist beaches.
When Nudefest was at newperran we used to have a beach day at Perranporth.
If you head for Gear farm, Rose and park about 200 yards passed. near t junction. you will see cars parked where they go on dunes to walk dog.
Google it and you will see st pirans church and Oratory a bit of history on your walk. keep fence on your right you then walk over MOD land it's a public right of way, then at end turn left walk to beach.
when on beach you will still rocky section on left at low tide you can swim around corner to small beach/ cave.
Enjoy.