What model of bike does Jock use in the film Young Offenders
There are some moving clips  at   
                
             but blurring detracts from the details

The red bike seems to be too small for the rider - which may be because he's just stolen it and has not adjusted to fit his height.  Noted it has a front suspension and a disk brake.

Also, most of the bikes used in the film look like BSO MTBs with front suspension - that is they're hard tails.  Also noted that only a couple of them have disk brakes - rim brakes being a mark of a BSO.  That's odd because one might presume a bike thief would steal the nicest bike they could, which would have a higher resale value.

The masks are an excellent idea for hiding the face of stunt riders, but riding in a rubber hood would be horrible in practice, due to sweat and limited visibility.

Specific to the Yellow town bike "It's a girls bike - its got the fanny dip thing"   from 
                
                It also has a 3 speed nexus internally geared hub at 68 seconds.

There's a brown mixte frame in the back of one shot - that looks like an 80s bike.

All in all, it looks like the bikes have been chosen to be representative of a low-income area, where old bikes live for years, and nobody would own an expensive bike.