The history in this case was more likely suppressed, I think, than lost. There was no knowledge of this among any of my living relatives, until I turned up the info while researching my family tree a few years back.
One person I spoke to, something of a local historian, told me that Robert was shot for "being an informer", and that he was "captured" as he was about to board a ship for England. This person did not seem to be aware of the RIC element of the story, however, and had no other information to impart. The trail ran cold there I'm afraid. I've been meaning to visit the bureau of military history but haven't done so yet.
Unfortunately, the son born from the 2nd marriage died in 1999 in the UK, just a few years before I unearthed the whole story. Its still unclear whether he had any children.