It's great to hear of the Argus again. I had the pleasure of flying 'PI' in May 1977 a few times, when it was owned by Leisure Sport. Those of us who were allowed a 'pole' loved it, and White Waltham was ideal for it's - shall we say 'characteristics.'
There is a picture of 'PI' on the wall in the clubhouse, taken at the time it was with LS. Dressed in Green with a nice big roundel.
Memories! Ah!!!