Hello, my pug 307(110bhp) has an intermitent starting fault. Usually first start in the morning and then after being at work for the day. Inbetween this it starts straight away every time. Spoke to a mechanic who says the Hdi engine does not use the glow plugs to start? The engine only seems to struggle when its been left to go cold which does make me think it is a faulty plug. any ideas please???