wrote:

In terms of climate classifications, I can readily obtain world
classifications, but am having difficulty for ones within the British
Isles, probably because generally we have weather rather than climate,
and that if we determine we have 'climate' there are many 'climates'
within the British Isles, I guess.

Anyhow, thanks for your help so far

Yes, the various global classifications are for making the
broadest of comparisons and associations with flora, land-use,
etc (insofar as they are for anything).

For the sort of very specific and very local use you describe,
it seems to me that the sort of data your really ought to be
seeking are single-station averages, extremes, and key dates.

Also, having recently established a small weather station on an
allotment site (in Luton) and seen the interest the figures
generate among many of the allotment holders, I would
encourage you to advise your groups to do likewise, and
they can then learn quite quickly exactly the sort of
climatological characteristics their site has (perhaps comparing
them with averages from their nearest official weather station).

They will need to be properly sited, though!