To add others that do this - Air Miles (as in airmiles.co.uk) do this and, if any of the main line legacy carriers do not currently do this - they soon will. Since the UK gov has zero interest in stopping these practices (could easily be done through the office of Fair Trading Standards etc) then you just have to do what humans have always done:
Look a the bottom line, decide if that is an acceptable price for the car/cake/tickets on offer and then purchase or walk away. I used to look at the charges item but no longer do as I presume that it is being fiddled and the only point of interest is the final charge (including any surcharge for using anything other than cash in a brown envelope.
Happy landings!
