Had four new tyres fitted as I was told they had perished (5 year old car low mileage) Cost of £530. Two days later tyre warning came on, back to National in Bearsden, Glasgow. Told me the valve was faulty and and said they had fitted a new one. A week later going out to a rural golf course tyre warning came on again. Had to abandon car in layby as tyre was nearly flat. Husband took it back, staff were exceedingly rude said they were too busy to look at the car but he could bring it back the next day. He then took it to Kwik Fit in Milngavie who informed him the tyre valves were old and cracked and although the tyres had been changed the valves had not hence the reason the tyres were leaking air. Kwik fit changed the valves and gave my husband the old ones, they also photographed the leakage out of the tyres for evidence. No response from National when my husband tried contacting complaints. Will stick to going to Kwik Fit in future and not go near National again.