Yes
https://www.tripadvisor.co.uk/ShowUserReviews-g186298-d6936786-r254260277-Eastney_Beach-Portsmouth_Hampshire_England.html

The BN web site says:

Grid Reference: SZ68039893

Terrain: Easy

Distance: Not Applicable
The length of the route can be varied.

QuinetiQ own the beach above mean high water and although they have not designated that as a Naturist beach,the beach continues to be very well used by Naturists. It's always worth checking with the http://www.eastneybeach.org.uk website for the most up to date information.

From the Free Car Park adjacent to the Caravan Site. Walk down the path to the beach and turn left. In order to avoid offending others Please do not undress within 50 metres of the footpath.

There are toilets and other facilities in the textile caravan site but it is unlikely that these are available to those who are not camping at the site. Park in the Free Car Park adjacent to the Caravan Site.

We went a couple of years ago and there was a good mix of naturists and textiles. With children we found the number of dogs running free to be the problem.

Thanks for the info John Gw, with a sunny weekend predicted we definitely intend to try it out.

Hopefully i might have time to get there on Sunday..

its large cobbles so you have to roll them about to get a comfy laying position
had an energetic group when threatened with closure
used to spend many afternoons there when had business on Isle of Wight