Hmm.
5000 pax per month. Divided by two airlines allowing for weekends, RE would be splitting their share about 175 ways, so that would be roughly 28 pax on each flight, supposing they got 100% of the share.
And that's with some cheap seats offered, not just all premium.
They'll be charged for a 70+seater anyway, so no point keeping a -42, but unless they really push fares to pull traffic off the LGW and LTN routes, then they'll struggle to make much profit.
If Flybe keeps the LGW fares keen, then only premium traffic will switch back and with the slots, only some of them, as you only get a half day.....
Haven't a Clue, Flybe have been looking into extra capacity on the LGW route as a priority, so depending on the impact RE make, something will likely happen for next year.