Hi,
Lawrie Armatruda serviced and resealed my Walther lp3 recently and he did a very good job.
He turns a whole new piston in aluminium which will take o-rings, rather than the original piston seals.
I’m pretty sure it was around £70 all in, including a full service, all the seals and a few spare o-rings and the new piston.
It basically future proofs the pistol for ever, as the seals will be probably be unobtainable in the future.

When you consider goths-waffen charge £15 postage, plus £10 bank payment fees it’s not bad.

Cheers,
Matt.