I thought the initial post was a massive enough infodump as it was without getting into the specific details of negatives or positives, Who Found What, How Long They Had It Before Returning It, and later recoveries of improved (colour/stored field/unedited/625-line copies), so did my best to avoid those areas.
The Celestial Toymaker 4: It was leftover from ABC's broadcasts, NOT from RTS in Singapore. Jon Preddle (who runs the BroaDWcast website) informed me this will be corrected in the new version of Wiped! next month.
Ok, I took my version from the original edition of Wiped (where ABC was quoted as saying it definitely wasn't their copy, and must have been sent to them fairly recently), so sounds like you're more up to date. That would be interesting, as it would be the only recovery which was sourced direct from ABC, right?
As for Dominators 3: Assuming that the BFI copies did come from Enterprises, then they'd only have a 16mm copy, which would have been returned along with War Games in July 1978. So the origins of the 35mm copy would still be a mystery, but one best explained by a cataloguing error missing something that was there all along. As Andrew Martin says (Wiped, p.155) "I'm very sceptical about the idea that the 35mm material for episode three of The Dominators was ever anywhere but at the BBC Film Library..."