I used to ride behind them regularly in the 1980s and they had a great following. (I had haulage behind 50 of them - many haulage enthusiasts had many more than that.) They used to run summer weekend specials to Skegness etc. behind pairs of 20s. We always called them Choppers. They often used to run into Glasgow Central/QS too and they were always a favourite on railtours.Are you not convinced? In my (admittedly limited) experience, the 20s have a particularly fanatic and dedicated following compared to, say, 37s or 47s, and they ususally turn out for stuff like this. May well be wrong though!