[Dalton]

Tamiya spring sets are both stocked here in the UK :-

http://stores.ebay.co.uk/Tonys-Tamiy...id=p4340.l2563

Or Hong Kong :-

http://stores.ebay.co.uk/Dinball?_trksid=p4340.l2563

http://stores.ebay.co.uk/stellamodel...id=p4340.l2563

Either 201/511/501 or 502 springs are all the same