A local machine shop has two sets of +30 thou and one set of +1.0 mm (just under 40 thou) of new old stock AE Hepolite pistons. £80 per set.
(They also have sets of standard sized Stag pistons but those come without rings.)
I'm happy to pick them up and post them onto interested parties at cost, as the owner isn't interested in posting. Sadly, no Sprint ones, not even TR7