Water in Condestate Pipe full?

I have a Worcester Bosch Greenstar with the condestae pipe routed indoors to a 40mm drain pipe. Today when the boiler fired up there was a "Gurglig" from the exhause stack. After Googling the fault i discovered it could be a frozen condestate - Not here in September - On further investigation i discovered the condesate pipe had water up to the bolier (Air locked I think) - I drained it down but the boiler will not fire up and remain running - It fires for a few minutes - You can here the fan - the Green Flame shows - goes out - blue light flashes - goes steady - fan starts - green light on - then goes off and blue light flashes. Please help