I was at a talk by Jim Buckmaster (CEO) at Edinburgh University earlier this year, he mentioned this. He attributed the lack of staff turnover to the generally

I was at a talk by Jim Buckmaster (CEO) at Edinburgh University earlier this year, he mentioned this. He attributed the lack of staff turnover to the generally relaxed work environment rather than one of these specific reasons. Seems like quite a cool place to work for a programmer, and given only 23 people work there it's not surprising few people leave. Anyway, the video is available here if you are interested, have a look around 8 minutes: mms://granton.ucs.ed.ac.uk/tech-entrepreneur/IE2-06-07/S07JimBuckmaster.wmv (maybe it was the jet lag but he's definitely the most chilled out CEO I have seen!)