Serial 109, when 1 A/B div was in Lincolnshire, with Div HQ at Fulbeck Hall, I believe that the following units used this serial:
-HQ 1 Airlanding Brigade & Defence Platoon: 109 on brown
-Signals section: 109 in red on blue/white
-No. 1 Light Aid Detachment (REME) 109 on blue/yellow/red
the front mudguard marking might be a section mark ie A company / HQ company i know some tank squadrons used a yellow square/circle/ or triangle on there front mudguard to denote which section they belonged to
Yes, definetively "109" you can even see a piece of the "1"
And white on black!!
Thought so myself about the triangle/square/circle, but no other pictures to prove it, the Forum piccy, also has something similar on the front mudguard, but not very clear
I have seen similar markings in a book somewhere which featured a Panda on the front mudguard, which is supposed to represent a play on the word 'Panzer' as they were an anti-tank unit. I have not seen many of these front mudguard signs and hazard a guess that they vanished early in the war....