I've got the same probs with my mundaneo but mine all happened at very low speed and didnt hydraulic lock the engine while driving .

Get the glow plugs out and turn over by hand to get rid of oil is sounding a good idea , im hoping that is what i can do and then just get the turbo rebuilt or get a recon one .

If the oil seal went at high speed then i could imagine it will suck its own engine oil up and could do untold damage . still worth trying to save the engine in it first tho , garages arn't known to tell the full truth all the time .