Well, I think the lesson is to try not to smash it up in the first place, it's a tricky fix and I got lucky. I picked up the replacement OLED from Gearbest here
One note, I say in the video "2 screws", there are another 2 inside holding the PCB in place, but you'd probably notice these without me telling you.
On the other hand, the firmware update is very easy. The site to get the updates from is here
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The link to the 2.3 firmware (which is well disguised on that page !) is
Certainly worth doing if you are using the camera for live out, and that OSD is winding you up !