I expect many of us claim exemption from MOT under Regulation 30 on Form V112G (not to be confused with Form V112). Post Offices have very few of these or prefer not to look for something out of the ordinary & say go & retax it at a LVLO because they have targets for the number of customers seen per hour & I suspect this may have an effect on the earnings.
Well I stumbled acros this:
Which makes life easier. I think the Reg 30 applies if the vehicle is used unladen, built before 1960 & over 3 tons.
Another interesting DLA place fo nosey parkers is:
Follow "Vehicle Enquiry" then put in VRN & make of vehicle & see what comes up!