Provisional to Full License

When I took out current insurance (2 months back) as Provisional License holder, I also got a quote for Full License, which was only 'bout £100 more (possibly due my age - at 66). Following a phone call today they now asking nearly £500 more, which nearly doubles my premium. Test is in 2 weeks, and 'if' I pass, then current insurance will be invalid. I see on other posts, 'cancel fee' could be, like, 30 to 75 quid. If they ask more I would be tempted to refuse to pay it, 'cos policy will no longer be valid anyway. Lowest quote (today) for new Full License is actually lower than current policy. So, shud I pay their 'cancel fee' and start new policy with new provider? - looks like that's the way to go...thks for any advice....