Slingsby T53/Dart
Derek Piggott had a bit of an experience after pulling a loop at the Farnborough Airshow demo but it was kept quiet. This was after the first weight saving redesign by Mr Slater, dad had joined Sigma prior to the first flight as previously mentioned.
Interesting comment about which Dart u/c it was, as in my notes dad had used the word replacement which I did not use in my earlier post.
Do not know about the Swallow name but will ask next time I ring.
Any more questions from that period please ask and I will mention them