Rich,
Very well done for getting to the stage of having the car back on the road. I would suggest ringing Club Lotus and asking to speak to Alan Morgan about your valuation, they will happily give you his mobile number if he's not there and he always is pleased to talk Lotus. your valuation should be a minimum ?25000 for agreed value, probably a bit higher wouldn't hurt and wouldn't be out of the ball park for a good +2 these days.
I still highly recommend RH Specialist cars and have just renewed my own insurance at ?28,000 agreed for my +2 and ?45,000 for my S4
https://www.rhspecialistinsurance.co.uk they are the only people I trust to do properly transparent retention of salvage and full agreed value insurance for our cars, whether they be concourse original, nice daily drivers or modified abominations like mine.
More photos appreciated......