Have sourced tyres ! I'm answering my own question....!
Paul Smeeton's bitz for bikes www.bitzforbikes.co.uk in Rochdale can
obtain a "Kings tyre" KT962 21x2.50 block tread tyre. They dont appear
on the web site as it "searches" by bike type. Just give them a ring on
01706344899 they had mine deliveed in two days ! I have not fitted
these yet but everyone says they should just about squeeze in.
Will let you guys know for sure once fitted.