ford fiesta diesel starting?

Hi,started my combi ok, tried to start again 5 mins later and nothing in START position,all lights on ok but not even a click,it did start eventually but not again.Changed starter with solenoid,no joy,will start from underneath bridging starter,a test lamp on ignition switch wires shows live when key is turned to START position so I don't think it is ign switch,where do I go from here,fuses look ok.X REG 100k.Cheers.