Thank you Mike, you have summed up the situation perfectly. If anyone is interested in the greater impact of the proposed development then a report is available online -
http://www.portsmouth.gov.uk/media/dc20051130r.pdfPlanning application No. 4 concerns the new development at Eastney, section 54 specifically covers the beach (extracted below)
Quote
Use of the beach
54. The area of beach east of the Camping and Caravan Park was formerly owned by the
Ministry of Defence until it became the freehold of Qinetiq. That area was the subject of
limited public access when Fraser was used for gunnery training, indeed the MoD
operated a red flag system to ensure the public did not venture into the foreshore area
while the gun battery was in use. With the demise of gunnery training the foreshore
became more accessible to bathers and walkers alike. However, as access around the
south-east tip of the sea defences was limited to comparatively short periods at low tide
that part of Eastney beach effectively became a cul-de-sac that discouraged extensive
use by the public. That situation provided naturists an opportunity to use part of the
beach which the general public did not ordinarily seek extensive use. The use of the
foreshore, above mean high water mark, by naturists was tolerated by the MoD and,
subsequently, Qinetiq as freeholder. The City Council arranged for the display of signs
to advise the public that naturists used the eastern end of the beach. Naturists do not,
therefore, have an occupational right in property law. Whilst I am sympathetic to their
concerns that the proposed redevelopment will significantly change the nature and type
of occupation on the site, and that the occupiers of the proposed development may be
less tolerant of naturism than the MoD or Qinetiq, the subsequent inability of naturists to
use the beach would not amount to a sustainable planning objection.
Unquote
I have a gut feeling that the new owners will consider the beach as private property possibly allowing public access with conditions attached - now there's a challenge!

Take care,
Steve J