I'm handing over the pc to my other half who is a commercial airline pilot
and gave me the information for the previous posting !

Adrian - your photo listed as 0910A would have been taken at 'local time'.
The photo was therefore taken as the clocks in the UK read 0910. BST, as you
correctly assume.

Zulu time is used by airlines and ships in order to simplifiy things... if
you depart London at 0900 local and land in New York eight hours later, you
will land at 0900 local (NY) time. For despatch purposes,it is easier to tell
the crew that they are leaving the UK at 0800 and landing at 1600. They will
have 24 hours rest, depart at 1600Z, landing at 0000z. In practical terms,
this means leaving at 0800 local time, landing in the UK at 1600. You get
used to it !

There was a historical squabble between the English and the French over which
line of longitude should be the Prime Meridian. We won, hence the PM runs
through Greenwich, but I recall this is why Alpha time runs through Paris (an
hour ahead) as originally, the French designation was used.

If you have a lat/long co-ord   (N)xx yy.z(W)xxx yy.z, using the almanac
published by the Civil Aviation Authority you should be able to establish the
local time (to the nearest minute) the photo was taken anywhere in the world,
providing you have a time and year identifier on it. I believe historical
almanacs are available (and useful) as due to Earth precession (wobble !),
any lat/long co-ord and zulu time will amount to a different local time in
any given year.

Another thing to remember is that timezones themselves are not a physical
function of the globe - they are not sited on straight lines of longitude
(many  have bends and curves) and they are often politically
influenced....(as a group of islands close to Oz during the 2000 celebrations
exploited when they petitioned for their timezone to be moved in front of
their coastline, rather than behind, to make them the first landmass to
experience New Year in 2000. Their petition was successful and the whole
chain moved 12 hours in time for tourism benefits).

Wartime photos of the the UK and Europe are not really going to be affected
by this, but if your timeline is important overseas you will need to access
the correct resources.