"However it is my view and others nearer the airline that the Airbus A319 would be a more suitable aircraft ?"
IMHO, the 737 leases were sending BE in the wrong direction in a crowded market.
By operating smaller a/c's, BE keep their niche. Are costs/seat/mile really lower for the E195, compared to the A319? I'd expect a slightly greater fuel burn on account of size, and isn't the config going to be 4 abreast, so more air being moved around in the corridors? BUT this can be counterbalanced presumably by lower airport charges from regional bases and also being able to extract higher yields through having to fend off fewer competitors.
Looking a bit further down the line, Flybe must have one of the quietest fleets around, which will become more important as noise based charging becomes more apparent. And aren't our Brazilian friends making some pretty good advances in the field of alternative fuels?