Has my mechanic overcharged me?

My car was recently MOT'd. They replaced two tyres and a windscreen wiper arm mechanism that wasnt working properly. They also moved one tyre from front to back. This cost me �415.00 (incl parts, VAT and MOT) it also includes 5 hours for labour. This seems like too much for the work done but I don't want to challenge it without some idea if I'm right. The windscreen wiper mechanism itself cost �95.00 which also seems very steep - its a Fiat Doblo so not exactly a fancy car. I'm a young mum with no idea about cars and worry all the time that they take one look at me and rub there hands together. Can anyone help with some advice.