Sausagehead: I assume BHX-MJV will be on one of the two leased-in 737-300s. I suspect there would be some payload penalties associated with doing that in a 146 (and don't really want to think about block time). I seem to recall BACX did a charter series BHX-MJV with Avro RJs a year or two back which was - I heard from the charterer - at the aircraft's limit or a bit beyond...
But hey! What do I know! Maybe a Q400?