Dear All,
It was an air traffic controller who originally said that PPRuNe would be able to point me in the right direction and how right he was.
Many thanks for all your contributions: I reckon that T-21 is right and my guess on the date is only one year out. Boston less than 20 miles from Coningsby: not that far to take 4 young boys on an outing. Now that I have a date and location it should be easier to research further. Should I find anything then I'll post a comment accordingly.
TTFN, Michael