I think the overlap is as follows:
- Alicante 5x weekly (Easyjet daily)
- Bergamo 4x weekly (Flybe 4x weekly to Milan-Malpensa)
- Bilbao 4x weekly
- Brest 2x weekly (Flybe 8x weekly to Rennes, but the distance RNS-BES is 240 km)
- Cluj-Napoca 3x weekly
- Dublin 2x daily (Flybe 3x daily)
- Faro 5x weekly (Easyjet 10x weekly)
- Kosice 3x weekly
- Malaga 5x weekly (Easyjet 1x daily)
- Palma de Mallorca 4x weekly (Easyjet 1x daily)
- Venice 4x weekly
- Corfu 2x weekly
- Reus 2x weekly (Easyjet 4x weekly to Barcelona El Prat)
Competition for Easyjet on 5 routes, but on all of them Easyjet still has a majority of flights. And these are just five out of the 20 Easyjet routes at Southend, so I think there is not immediately much trouble for them.