I finally found my tape. In total around 2-3 minutes (interrupted). Only one PE scene, around 1 minute. First, one boy in shiny, light red shorts and later the sporty, blonde boy (last pic in the middle) in light green shorts, probably the same brand, unknown if shiny. Can anybody identify the brand? Looks like an “LO” or <O. On the sides are white patterns like a row of “><” .
One more pic of a chubby boy sitting in medium blue shorts in the main entry (only shown from a distance). There’s also a girl in pink shorts (probably not shiny) and the chubby boy in large, white shorts (non shiny, pic 4 on the left). Anton is on the right. He usually wore belted, light blue, purple checkered cotton shorts/knickers.
The sporty boy is later shown at home sitting on an exercise bike but in long, light grey cotton pants. I haven’t made a vid, just some few pics at higher res.