DUB_LGW - EI and FR

[ayroplain]

The pic here shows the routes taken by EI and FR between DUB and LGW. I'm curious to know why they differ so much. Why is one route chosen over the other?

http://img842.imageshack.us/img842/8938/eifrdublgw.jpg (http://imageshack.us/photo/my-images/842/eifrdublgw.jpg/)

[Skipness One Echo]

Slightly off topic but I know LHR ATC were keen for Aer Lingus to file via BUZAD rather than COMPTON for Dublin as Southerly delays were more common than those to the North but to no avail.