MerchantVenturer, the CEO has said in various presentations that the focus on growth is to 'secure the fort' before moving on elsewhere. BHX is the first new base in many years. I am in no doubt that there will be a new base at some point - when I'm not sure, they keep understandably tight lipped - but another big base near London would seem to be a key strategic move. Therefore, I fully believe any new base would be somewhere in the South East. STN would fit that bill.
Jet2 are now becoming a major player in the UK, the fleet is certainly one of the largest now. I think the days of growth into smaller, secondary airports is over. There could be some surprises, but I've no idea where the CWL rumour came from...?