Perhaps God says “you’ve got the tools and the head isn’t that difficult a job... why are you wasting my time with this sort of request?”

HOORAH, well against all odds the vacuum idea with air compressor worked, the bit is out through the injector hole.
My wet n dry vac had a 22 mm tube taped to the hose and was a tight fit in the injector hole and I borrowed my friends portable workshop compressor I started the vacuum and applied bursts of air through the glow plug hole and after a couple of hours of no joy I got the wife to take over the air jetting as I rotated the crankshaft by hand and within a few goes I was about to give up I decided to look in the vacuum cleaner and hey presto the electrode was there.I don't know if it was divine intervention,luck or something else but I'm well happy.
I also found THE VERY TIP of the removed electrode IS magnetic so for anyone wondering if it's possible on a TD4 to get the tip out I can confirm YES IT IS I'VE DONE IT.
I am in the same position with my last glowplug the electrode is broken off and stuck in the head but this time I'm going to buy a £36 tip removal kit and try withdrawing it as I don't want to chance my luck again but at least if all fails I know it's possible to get them out.

Well done.