My car has failed it's MOT and I've got a price for repairs ~ is it worth it?

Hi All, my car (P reg Mondeo) has just failed it's MOT on a front ball joint/suspension arm, 3 corroding brake pipes, hole in the back box and on its emissions. The garage have given us a fixed price of �225 all in, including labour and MOT re-test, any other bits and pieces or parts costing more won't be charged as they have given us a fixed price; we have no idea about car part costs etc, does this sound reasonable or not? sensible answers only please, thanks in advance....