Always liked the Bocian. Good looking glider. I owned a Mucha 100A which was basically the single seat version. They're nearly all gone now, more's the pity.
My first solo was in a Bocian, from the Bath, Wilts and North Dorset GC. The Park. UK. We used have three of them. We have three Puchacz now. I would love to visit your club one day and try a gravity launch. Looks fantastic!
First flew a Bocian at Nympsfield after basic trainig and early solo flying in T49 Capstan, T45 Swallow and T21 Sedbergh. Bocian was a beautiful glider to fly but totally unforgiving of any incompetence or neglect. Sadly not many left after all these years.
This isn't really about thermals, in the mountains you get lift from the wind going uphill (slope soaring). This seems to have been a very calm day, so perhaps not much lift there.