Just an observation, but if you look at the AAIB report I think its pretty obvious that the Yak pilot did not do/was not positioning correctly for a RIAB. The implication is that he did an unauthorised flypast of his house then turned the wrong way up the base leg to reposition. If he had continued to initials, flown through deadside and broke into the downwind element of the cct at an appropriate time (having visually cleared the downwind leg) we wouldn't have been having this argument.
Regardless, as an aside, a RIAB is actually very safe as long as everyone involved knows where to look.