vauxhall combo won't start

[Alexandria]

turning over but just not starting just replaced both relays and have recently had new glow plugs. Any ideas please

[stanleyman]

A deisel needs correctly atomised fuel, sufficient air, correct timing, sufficient high compression with a fair turn over speed and sufficient heating assistance to ignite the fuel when cold. If anyone of these essentials is missing, worn or not operating properly then the engine may not start. You need to check through each system to eliminate it as the cause until you find the problem. A Haynes manual from Halfords would be very useful.