I'd say 60-70% of the MAN-TFS flights with EZY go down via the Bay of Biscay and Portuguese coastline. The other 40-30% of the flight southbound go out towards the southern coast of Ireland and then follow a route called Tango 9 (one of the Atlantic Tracks running North/South) which spits us out on the northwest corner of Spain/Portugal.
The same probably goes for Northbounds too, maybe a little less use of Tango 9. As someone stated the Navigation fee's are less avoiding French Airspace but the fuel usage is marginal so no need to get the environmentalists concerned.