I have just had my Citroen C5 MoTd. As always my neighbour is a mechanic and we go over all the MoT requirements before the test. Today it failed on excessive play in the lower ball joint. Yesterday we checked this a no play was evident. So in driving 4 miles this wear became excessive. They want £100 to do this or £26 for a retest if we do the work ourselves. Who do I contact to check this is not a scam for extra work? I did get an AA reduction of £17 on the test. It also failed on the passenger wiper blade not clearing the windscreen. These were new blades so I challenged them and showed the mechanic it cleared OK he said it didn't when he tested it but he agreed it was OK now. Help.