Most of those flyers are from housing agents, or companies having something to promote. Maybe the town council can help by putting up a notice board, similar to the ones by the RCS.
So whoever has something to promote has to approach the town council to have their flyer pin up on the notice boards. ( of course by paying a very small yearly fee.) To make it more presentable, all posters must be of a similar standard size.
Something has to be done, otherwise the haphazard distribution of flyers won't end.