More info...
Have seen the specialist orthopedic knee surgeon her ein the UK (Leeds) and....he can't tell for certain it is a meniscal tear from the X-ray, and thinks anMRI scan may prove inconclusive too. He is however fairly certain it is a (rear) meniscal tear (having twisted my knee every which way!) and has referred me to a physio for 6 weeks. If that doesn't improve things he thinks I'll need an Arthroscopy(?)
So I'm off to the physio (though I read that meniscal tears can't heal themselves?)
Cheers