[The Philpott]

2) At one point i proposed trying differential expansion by submersing the case in hot water, but in the case of the meter concerned, i understand it didn't work. A hairdryer might deliver more useful localised heat, in conjunction with WD40 or some such release agent. This question has come up before on here so you should be able to find it on a search. The guy in question did manage it eventually but i can't remember how.

Slightly tongue in cheek I also proposed a last resort method of removing the instruction plate to expose the rear, then drilling thro' the steel in strategic places, putting a drift through the holes and tapping the bakelite case free.