A319 is not right for those routes
The costs of operating an A319 on longer sectors and on some sunshine routes would be so much higher than the ERJ-190 at Southampton.
Bournemouth will only work with bigger aircraft and lower costs/therefore fares.
A321, B757, A320, B738 would be good as it would allow for lower fares to better compete with Flybe and other Full service operators at the London airports.
Bournemouth has a niche market that fits well with Southampton: mid to longer range routes with larger capacity aircraft and lower fares. It remains yet to be fully exploited, and the economy is still sensitive. I believe BOH will rebound in 2012/13.