In my engineering days, anything fitted with loctite (screws etc), were given a sharp tap on the end before attempting to remove. This seemed to break-up the loctite and the screw could then be removed easily. Not sure how it wold work on a watch stem/crown. Perhaps giving the crown (stem-up) a good tap on a solid surface might do it, but not sure if enough force could be transmitted.
thanks Jdm. I was thinking calipers and yes will probably pick up a press as suggested.
will try just to break off the rest of the glass then without mangling the case. seems like not worth the hassle to try to work out the pushers as they seem to be fairly fiddly to deal with so best avoided for me.