It's hard to answer, as you will have been told insurance is priced on your circumstances. But I personally wouldn't pay that to insure a Vauxhall and would worry I was paying way over the odds. My 1st car (Corsa) was about £8-900 so between your younger age and different postcode, you are being asked x5 as much. (Is £4k more or less what the car costs?)
I'd try quotes for some other cars as they might just really not like that one and its not a good deal if you need to pay extra 1000s down the drain (possibly for years) when I fit passed I wanted a Renault Clio as I leaned in one, but insurance was x2 the Corsa for some reason despite a v similar car.
I'd never get black box, it gives the insurer way too much power imo. I've just heard way way too many tales of 'I love my black box policy, oh... right up until I got that letter cancelling it and essentially putting me off the road' (It's half the price for a reason)