Hi Marco,
F236071 looks to be from the Guards Armoured Division. Not too sure about the AoS though. It doesn't look like 2nd Household Cavalry Regiment their Armoured Car Regiment only other I can think of off the top of my head is from RASC but lower part looks too light to be red over green.
What search method do you use. As you say the database is huge. I am having trouble finding my way around.
Cheers
Kevin