Originally Posted by stut
Of course, up until now, there's been no such thing as a BD fully-inflexible fare. All fares are changeable for £30 plus fare difference (which has worked out well for me on several occasions).
It's not that the OP wasn't prepared to pay a change fee, but to try to apply an additional change fee to an already flown segment, where a point-to-point one-way would be cheaper... Now, that's just silly.
The way round this, of course, is to travel from CDG, where they just put you on any old flight, and upgrade your fare class for fun, too

Thanks Stut, that's entirely the case. I would have had no problem in being asked for the difference between fares for example, which would have been around 50 GBP.
For everyone in this forum who has such faith in fully flexible tickets, I have on 2 occasions (Air France and United) had fully changeable 'Y' tickets and been told that, tough luck there's no seats available on the flight you want to change to.