Thanks one and all for advice provided as I've worked my way through the rejuvenation of a friends Airsporter. I'm rather pleased with how its come up, I think my friend will be delighted, and a few shots with some Marksman no.2 5.6mm pellets to check the zero and it'll soon be back in the hands of its owner. Its given me great pleasure to fettle this old gun over the last couple of months.

http://imgur.com/a/VE4r6dh