I'd be happy if the stupid EPG
entry has to be longer than 30 minutes in order for the programme to have an internal ad break" law applying to kids content would be dropped, as that obviously can be bent anytime by using (annoying and messy) 31 mins long slots, after Brexit
At least the "your programme has to be longer than 35 mins" initial proposal has not been successful, this way making linear "31 mins+ 29 mins" slots would be impossible, without fillers and very long ad breaks,, on kids channels. Not surprised by these laws, in general Belgium and many European EU countries hate "linear" schedules made up of "regular" slots, at least when available
But, if Brexit also means (among many things) that the 12 minutes per hour ad limit cap is at risk, then it's just not worth it.
But I don't think they would go beyond 12 minutes even after Brexit, since laws (particularly for UK public channels) are stricter in the UK, when it comes to minutage. And that's obviously a British decision.