Easyjet did have a Luton - Liverpool route for quire a while in the early days but it was not viable. Similarly bmi had a Liverpool - Heathrow route for a while and even tried a SF340 on it but again it was not viable.
Turning to routes to Paris, there are a lot fewer services from the combined London area airports now compared to pre the tunnel e.g bmi to CDG and Orly from LHR.