LCY is great way to access London and I've used it dozens of times with Euromanx and VLM, but only once with RE, on the basis of high fares, clapped out aircraft and significant puntuality issues. It was always going to end like this, one day.
Can't imagine that BE would want to compete with themselves on LGW and LTN, unless it was a tactical move to keep out someone else. But is there realistically anyone else? Manx2, Eastern?
I'd hope that the probable migration of c4k pax per month to LGW and BE might tempt them to look at an E175 for that route. Otherwise, the numbers suggest there will be a lot of full Q400's on Mondays and Fridays.