The following was brought to my attention and I'm wondering if the IWM still has the model depicted and also what was the subject matter of the others in the series as this one is numbered No7. Anyone have any info or thoughts !
The IWM does indeed still have this model - I last saw it on display in London.
As you may know, the IWM was originally at a different site in London to where it is now and had an original Thornycroft AA lorry in it's collection. But space was pressing and it moved to Thornycroft, who provided the model in return. After a bit of a chequered history life went full circle and the very same vehicle made it's way back to the IWM collection. It has since been restored and is on display at Duxford.