I would highly recommend Ren O Man, Toft Green York. No website but phone 01904 656700.
Took my Clio there when I thought the
had gone, and on the phone he said "get it here asap, don't keep driving it." Got it down there and within the hour he phoned me to say they had cleared some faults with the diag, and had replaced the spark plugs! Turned out Nationwide Autocentre of York don't seem to bother changing them at services!!!
Its solely MOT and repairs, and is literally a backstreet garage, but it is a small family run concern with excellent service. Yes, the bonnet had two greasy finger marks, but it was kept securely overnight, and where else can you have a morning conversation about your Clio with the owner, his wife and his mechanic son?! Total cost for run on diag, fault clearing and new plugs - £75. Also listed minor faults and upcoming repairs, e.g. cambelt date etc. Very good.