I would agree that there are hardly massive holes to fill with the demise of TCX. If anything, they may want to consolidate and lift yields at those locations. Unless slots are so scarce to warrant a land grab but I doubt it.
As for BOH, Jet2 have no presence at LGW so this could potentially pull demand away from the likes of easyJet and Norwegian. Could be quite strategic to do this especially if they did a split operation between BOH and SOU? 2 aircraft each.