Nicely done! Just like singing while lying on your stomach is not easy, so is doing the single spey for distance while seated. On a personal note I find it very humbling as I am far from mastering the single spey while standing.
Bear in mind the Single Spey cast is one of the most difficult casts to master (if the not the most difficult). There are two keys to master it IMO. One is mastering the lift and being able to feel the line/head leaving the water and becoming airborne. You are suppose to start you sweep a moment before the leader/tip leaves the water. Timing is critical. The other key is using body rotation to sweep and change direction. I recommend you take a look at the video below: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-P0zZLKrE2vg.html
@@janusz.panicz I didn’t notice your body turn and focus on the line, though it appeared you had everything else under control with your rod tip high and the rod direction was spot on before you turned back to your target line. Does that sound about right?