I believe that KLM will have extra capacity by way of more flights by the large variant of Embraer
While Aer Lingus drop their 2 sun routes, they will reinstate their 4th LHR rotation most days of the week. Ironically, on some days of the week BA have less seats on LHR than Aer Lingus... BA schedule looks like 4 or 5 daily.
It sounds like Flybe will have the greater frequency on LCY or large plane I should say, though not 100% sure how long that arrangement lasts until. Didn't they put extra capacity onto BHX at some point.
I should thing that 2020 will be more or less the same as 2019...