Perhaps I'm getting forgetful in my older age but when did BA.com start showing prices for individual legs of flights without including the taxes - I don't remember seeing this before. (i.e you only see the actual price after you've selected both outbound and inbound legs and clicked "continue").
I'm just looking at flight prices for one of BA's recently announced routes (LHR-Chania) and I can see HBO fares for £30 in each direction but, when it's only after I select them and click "continue" that I see that the trip isn't going to cost £60 (which, admittedly I thought was strangely cheap) but £111 instead.