The current edition of Strike it Lucky seems to be going out in some strange letterbox format at the moment.
They've also butchered going into and out of the breaks. The last time they showed this series they hadn't edited it. I really don't understand why they fell the need to edit something that really doesn't need it.
Sometimes the "Christmas Specials" of Strike It Lucky (which was almost always an otherwise normal episode but with Christmas decorations all over the place) had a longer running time, which Challenge used to shoe horn an extra break into. On those occasions they'd force the break and their own break caption, so "end of part one" didn't apply any more in those circumstances. For that it was understandable. Annoying but understandable.
But to do it for a show that was only ever half an hour and even to this day would have only had one ad break if it was made today in that format, it defies all logic. Strange, really strange.