Piggyback model override to set custom route for individual application page

e.g. /applications/1108/rushmoor/14/00556/CATPP

Copes with / appearing as part of the reference (try to ignore the local
assumptions that 1108 is the ID of application 14/00556/CATPP, also
the short name for my example authority is rushmoor)
Switch off routes we're not intending to support