Freelander heater plug snapped

While trying to remove the last heater plug from my 2004 td4 freelander, it unscrewed just like the rest but when I withdrew it half of it was left behind!! So basically the heating bit on the end and the piece that goes up through the centre of the hex are left behind, anyone got any experience of removing these with out taking the head off? Or can I just leave it there!!!!!

try drilling a hole down the middle part way and getting a small stud extractor and get it out that way with a little help from mr wd40 or try putting the other back in and warming the engine up first

There's a man in Carlisle can get them out for £75 plus I think £35 an hour travel he company is called extract engineering I know it's a bit far away but if you snap a bolt extracter in the head the head a knacker but me personally as long as the other 3 are working I'd leave it well alone as I was told to do so by Land Rover themselves the td5 only has 4 heater plugs to start and they're a 5 cylinder