I recently became another victim of this scam - Charged £192 for an, almost, invisible alloy wheel trim scratch that I did not cause. Avoid this company.
I booked via Holiday Autos - It is time they protected their customers by deleting Green Motion from their suppliers list.
Fortunately I took the optional excess protection insurance from AXA so anticipate getting my money refunded.
Yours is just one website where you can read all about GM's dishonesty.
Just Google and see it all. The most damning is an article in The Guardian newspaper - October 31st 2015.
Or try the 1 star ratings on this one - https://uk.trustpilot.com/review/greenmotion.co.uk
Even Trip Advisor join in.