What o-rings for Associated shocks

[Mash Potato]

Looking to re-build some associated shocks (B4 and B44). Obviously I could and would normally use the standard o-ring seals, but there seems to be a few options so I'd like to see what people recommend.
I've read about the Nortech whities which seem to have a lot of fans. Looked at buying them, but frankly the P&P on their website is too high so that's really put me off. I realise postage has gone up recently, and the charges are also to cover packaging, but even so it's very high and more than the seals cost. Do any shops sell them?
Any other recommendations?