Has anyone actually said to you that the postcode is a problem ?
Also if you are willing to transfer risk, 3rd party is an option ( add fire theft etc ).
Then there is the value question. Agree somethung sensible? Offer large excess?
W.r.t mods...its a case of how much you can claim on them, when, and where. Eg. A towbar will typically lower your insurance a bit. So maybe again, just agree value on the mods.
Finally, have you ever had a car ever? All insurance entites will entertain an internaltional no claims certificate (with x years, the value of x deviates from one to the other, but it does go upto 4yrs I found ).
Do you also have an international permit to drive here (ie not based off your UK license ). If so, that too will have a non dramatic reduction in insurance.
Post finally, £1500 as the first off, for car parked out on the street for a car originally valued at over £40k is not a bad price per se. A lot of the prices the old hats are quoting here are built off ncb/business/term/value situation. Dont beat yourself up over it. Remember santa will bring you a 20% discount at the end of yr1.
Post finally finally, put in a black box.... maybe just ask the jokers what you can do to bring it down, speak to brokers, your neighbours, see how you can mitigate riak, transfer it etc etc.
Post finally finally finally, maybe get a friend to introduce you to their insurance company and ask for an intro NCB. Aviva and directline etc have all been known to do this (but they are also the kind of companies that claw back and increase prices at every opportunity - so read the fine print )