bmm[23] - Austin K9 {Loadstar}

Austin K9 fitted out as a radio truck - seems to be being used as the PA system for a rally.
Has both civilian and military regmarks, respectively ... YSJ 339 and 74 BG 68
The K9 was a modernised 4x4 military variant of the Austin K2 developed post WW2, the Loadstar was the civilian version.

en.wikipedia.org/wiki/Austin_Loadstar

Posed in front of the main museum building - and it's not an optical illusion, the wall really is curved.