Ian (And Bill), many thanks for your input.
I will download the service manual this evening.
Out of interest, our local Lotus Dealer has quoted £337 for the whole job: Remove bodywork, replace both headlamps (The reflectors have gone flaky as it happens), repair the bracket (A common problem apparently) then reassemble.
I guess the cost is not too bad for that kind of work if you include both headlights.
Anyway, we will make a judgement after reading the manual.
Thanks again for your help