Regarding fleet letters and their purpose in life.
I was aircrew on the SH Force and the registration being painted in small letters on green rendered it virtually invisible at any distance. You soon became familiar with linking fleet letters against individual airframes even though they were normally referred to by the number (only) element of the registration. When walking out to a large flight line in inclement weather, you wanted the journey to your
allocated steed to be as short as possible, and the large fleet letters could be seen at a distance.
Of course this did not stop aircraft that had not been signed for being 'stolen' by crews who had walked to the wrong aircraft! .... as has happened on several occasions.
If anyone has air to ground photographs of Shawbury village from the Chipmunk era, I would very much appreciate seeing them.