Clattery when cold
Join Date: Feb 2012
Location: United Kingdom
County: Greater London
Engines with no compression won't run at all, under any circumstances, so it must have had compression at that point. Did you manage to stop the engine?
Your symptoms sound like diesel runaway, when the engine starts burning its sump oil as fuel, usually via the turbo bearing failing and allowing engine oil to be drawn in through the boost pipes. Left to its own devices the engine will only stop as it runs out of oil, by which time it will have destroyed itself quite spectacularly. See Youtube for examples. If you managed to stall it or otherwise stop it before that happened, it should be OK.
A runaway wouldn't snap off the glowplugs. A garage might, trying to take them out to do a compression test through the holes.