I personally would go the modular route. If you can afford both the IR and FI(R) then so much the better.
However I am saying this having not actaully gone through either route and tried to get a job or anything, and many will tell you it is easier to find work with an integrated ATPL from Oxford or similar.
If you do decide to go Modular, you can find the complete list of approved schools on the CAA website and shop around to find the cheapest (if that's what you want).
TB
