I looked on both RAVE and my TF handbook which both quote 185/55 for 15" on the front so that wont help you, I thought our testers were a bit jobs worth but yours seem even more so. Over here we have had a rule on tyres over 10 years old being a fail, whilst looking on MOT requirements it appears this only relates to front "steered" wheels on cars and on the rear of minibuses unless they have a twin wheel arrangement, go figure.