Cheap is not always best - and cheap for one is not necessarily cheap for all - insurance really is a post code lottery. Two years ago I moved 2 miles up the road changing my postcode from CR0 to CR6, it made zero difference on the Mas, wifes Mini, daughter's mini was £50 increase and other daughters 10 year old Peugeot was increased by £250! work that out.
My first year with Aviva was less than £500 fully comp - this year with e-sure it was <£400, Comparethemeerkat quoted up to £3000.
The best advice is shop around, some companies offer good service - others not so, truth is unless you need their services for a claim.....................