Try http://www.confused.com for an online quote, but for the charger they will need more info.
I’m with Bell Direct http://www.belldirect.co.uk they don’t mind modifications.
Also try Osborne & Sons 020 8388 6000, they specialise in Japanese cars, including grey and modified.
Or Adrian Flux 08700 777888 they have been dealing in modified cars for years.
But don’t dismiss the big insurers, try all the 0800 numbers; they are all switched on with modification nowadays.