TC had something like 45 aircraft in the UK market. Allowing for some over-capacity, it's reasonable to assume that existing players will add to their fleet plans by perhaps 30 aircraft - all other things being equal. Expect Wizz, Easy, TUI and Ryanair to be operating between them an additional 30 aircraft by next summer.
There's not much room for a new carrier when you look at it that way. Especially as any growth would need to be price-competitive with some well-established low-cost businesses.