Hire car dilemma - who to book with & avoid extra costs

[popdriver]

So, this year I went with a BA fly drive and all the costs for the hire car were included and Avis were good as gold and didn't charge me anything extra at all.

Next year I don't have a package as the pricing doesn't work, it cheaper to book deprecate flights & car.

So is this to good to be true, for example if I go on holiday autos and price up a mini van for 18 days it come to around £600

They say it covers all taxes, insurance, zero excess so it seams to read right.

It does exclude accidental damage to tyres & windows etc but that's only £3 a day to cover

Does this sound right, has anyone else done this and been charged extra?