Sitting here in the Wing after flying in on BA0027 - my journey started in AMS.
There was a search string posted somewhere that works on ITA (I think)
Check the ultimate guide and dashboard - I'm sure it's there somewhere.
Personally, I just check the prices on BA.com and see if I'm happy. I've ex-EU'd a couple of times when the LHR direct cost gets silly, but I wouldn't go too far out of my way - I think IST sometimes comes up as a low cost starting point, but 4 hours each way to do it?