So, should we pull these same units out of the 777's now?
I don't think that's what will end up happening. The three paragraphs in the section
Emergency Locator Transmitter (ELT), on page 3, read to me as:
The device is not a new design and has a proven history. The AAIB are looking into the possibility that a short, external to this device, caused the problem with this device, on this plane.
By the way... and just putting it out there... but before everyone got focused on the main battery/apu battery catching fire... I think there were reports of these batteries being flat/failed and having to be replaced...