£300-£400 maybe less and i have used either bell admiral or elephant last 3 years one each year as they tend to beat eachother on price each year
Also try adrian flux etc try go compare and all the comparison sites and then ring them up direct and knock more money off 
wow, thats a good price. Im 31 and been driving for 7 years and have 7 years NCB. I got some quotes of gocompare for a mk5 gti 2.0 the lowest one with a low excess was £1685.00 or something like that, others quote were between £1200 and £2000+ with the lower ones having a compulsory excess of £3000.
I also tried another golf I think a 1,6 sport with alloys and tints added and that came to £1554 or something around those figures.
I love the look of the GTI mk5 but the insurance is a killer. I see some people on here paying half what Im paying, maybe they have looked in the right places lol. I havent tried any of the specialist insurers or anything yet as those original quotes put me right off a GTI.
Right now I have a Peugeot 206 and Im only paying £477 for insurance for it from my renewal at the beginning of the month... quite a leap for a gti over a grand more.
Sorry for the ramble maybe I should make my own thread? sorry