First, steer clear of the 10 month bonus accelerators. I had one with Admiral a couple of years ago, but other insurance companies (mainly ones that do not offer a 10 month accelerator) do not accept this as a NCB. You're better off paying for an extra couple of months and earning a full NCB.
As for cheaper insurance, try Admiral. You're just going to have to expect high prices as you are more of a liability with your record.