Not surprised, insurance premiums have gone through the roof this year.
Instead of the standard corsa/saxo/clio brigade try and find a car that's a little bit different, something most 17/18yr olds won't think to buy.
I had a 1.8 Merc 190E at 18, my insurance was less than all my mates on boring hatch backs.
It was RWD, comfortable, mates loved it and my parents were happy because it was safe. Plus v cheap to run and buy.
Other ideas, Volvo 340, BMW E30 316 (maybe), classic mini, Audi 80...
You really just have to plug a load of cars in to confused.com and see what comes out best, ignore the insurance group on older cars less than a 1.8 they have less of a baring.
Also sometimes FC is less than TPFT, so don't rule that out.