Originally Posted by
chris1979
are you saying that there's an extra charge for using Amex?
or saying that paying £250 in tax is an expensive way of getting a few hundred avios?

There's a £2.50 charge for using a credit card.
So, for me, there will be a point where it is worth using the card. With the BAPP, it'd be around £200 (300 Avios, 0.67 pence per Avios). With the former BMI Amex (2 Avios per £), it'd be a bit less. Some may be willing to pay more per Avios.
nobbyclark said he eared 750 Avios, (presumably £500 road tax) so that's a good deal at 0.33 pence per Avios.