You've not done
too bad, in that my quote the day after I passed my test for the lady (The V6) was something like £2600
Be aware that, incredibly, once he passes his test, the quote will go
up - mine did. (though it had come down significantly from the original £2600, because by then I'd had my licence for a couple of years - though hadn't actually driven a car in that time, and therefore most likely a worse driver than when I passed my test two years previously, ain't the system great

) I imagine the reason it goes up after passing is that as a provisional driver you're supposed to have someone in there with you at all times, correct?
All I can say is try reducing the value of the car, as that also has a fair knock-on with insurance cost. Also The other thing is there'll be a 'sweet spot' on mileage. I went through literally dozens of online quotes, to find the mileage that is the cheapest. Again, bizarrely, saying I was only going to do 500 miles per year was a fair whack more expensive than saying I was doing 4k. So that's 3500 more miles I'm on the road and technically more likely to have a crash?!? Weird! I think my eventual sweet spot was 6000miles per year. The indicated mileage on the speedo ....um...
can be changed, not that I'm suggesting such a course of action, as 'twould be illegal, of course...
Hope you get somewhere. The best you can do is get something which won't have lost much value when he comes to sell. In the case of a brand new car which is very cheap on insurance/tax but you lose so much in depreciation/extra you're paying on the finance. But at a £1200 Corsavan I think you're already pretty much there.