Decided to give these Russian caps a go, they are 2.2uf 63v 5% PETP (Polyester) Type K73-16.
I bought a lot of twelve off e-bay for £2.64 + £5.30 shipping from the Ukraine. That works out at  66 pence each!
I'm running them in and will give full feedback on how they sound later. They sound pretty good from the start, so look promising.