i read this as well on the internet but unfortunately it was a few weeks late as i've already broke 3 glow plugs in the head.

Theres a good video clip of a mechanic using the klann tooling for removal of broken glow plugs on a merc vito but at £1800 is a bit expensive all though it did look very impressive.

£210 + postage for a tool that supposed to do the job is more affordable and its got to be better than removing the head.

I remember many years ago an old mechanic made cups to sit round the cylinder head studs on a V8 Triumph stag so he could tip coke down the studs to loosen them up as you couldn't get the heads off without removing them, it worked on a couple but not the worst ones as they just broke.