Sorted...

I didn't have a valve tool so got one off the net. £2.95 incl. 2 x valves and p & p.

Tried the wheel off the bike first. Took valve halfway out and back again. Worked. Did same on the bike wheel and that worked too.

Still don't know perzactly what the perps had done but am a lot happier now. Need to go to docs next week and it's 2+ hrs on buses.