Thanks to all who replied.
The losses which prompted the question were numbers 8 and 9 in Beeayeate's list, they were in exactly the right time frame. I'm quite sure that there was another at about the same time though, possibly in February? 30 something year old memories say there was one a month for three months.
Does anyone know why there were 2 (possibly 3) identical accidents to 13 Sqn aircraft though, was the cause ever found?