OK - so the consensus here is pretty much what I thought - just get it sorted out, no matter what. Yes, I do expect some expensive bills - but I have never laboured under the misapprehension that aviation is cheap. It's cool, it's magic, it's the only reason for living....but it's not cheap
The only thing that I might be able to add to this discussion is that I am pretty sure the governor was ON - I was a bit overwhelmed in the confusion immediately after lift off, when I felt the overspeed before I noticed it, and toggled the gov switch a few times, so I'm not 100% sure, but I am 95% sure! I had noticed that the throttle was very sticky as part of my pre flight tho - spent 10 mins or so wiggling the thottle - and I'm not sure how the gov works, but I strongly suspect that the sticky throttle was actually the problem. That said, I may have left the governor off - student or not, we all make mistakes, me maybe more than most - but just thought I'd mention the "sticky throttle" issue. If the governor couldn't overpower the stickiness, and I had a correlator-driven overspeed, well, I guess that means a sticky throttle is more serious than I thought, given that I'm now going to be getting the damn thing torn down. (Or, hubs inspected, tail shaft wash out inspected, SOME engine looking at (please God not a bulk strip, but I'll just do what the grown-ups say...)
It's a low time engine and brand new dash four blades. Yeuuuch. But collisions with Mother Earth are worse than telephone number bills eh