I thought SOU
was unable to handle the 737 on a regular basis due to the runway length and size of the facilities.
I thought the occasional 737 charter from Air Europa or EuroCypria put a struggle on the facilities and had to be specially timed not to arrive during their busy period.
I think Exeter may see some 737's as the Mini Hub there FlyBE has been operating is doing very well and they can comfortably handle the 737. This will free up some of the BAe 146's to be operated from Southampton.
Since when have airlines been able to obtain "Brand New" 737-300's, a their website states? As easyJet is disposing of their older 737-300's over the coming month's this could be where they are obtaining them from.
At the moment they have only made this one press release and everything else is speculation!