btw , had another look at the picture - seems a FFR (spade lids on wing tops) - that started --HG-- 1980 , but in fact you have rationalized axles (have 11" front brakes , rather than early 10") & that puts you certainly after Nov. 1980 . No rear wheel arch toolbox (underbonnet from abt. 1980) . BIG plastic grille badge (is a dating feature , but I forget) KA I think - so I guess earliest 5mb engine is a --KA--
The odd contract did have a mix. of glass and plastic bug-eye lens , but you can't go on that.
Defender mirror(s) often fitted in service as soon as they became available.
Seems a local hood , roll up eaves buckles and flap - not a normal feature but good to have.
Seems all in order , few more pics and a bit of a think - I may be able to zero in on the build date better , could be a --KB-- or a --KC--