Two things - 10,000 seats might sound like a lot but it equates to 5 days of flying - do the numbers....CWL will be a short term thing...just wait and see , I would not re - locate to CWL.
Amazon Man have a look at the SOU runway length, diversions and lack of Navaids. No way a low cost can operate there. Re the very limited 73 operation you will find that most are foreign registered - different rules than British registered ones...Some aircraft have to either stop for fuel en route (costly) or leave empty seats (Costly) SOU hasn't a chance of attracting a low cost operator. EMB operation is about the size of it.