Sorry, I realise this reply is too late for you Nick, but the reason
you didn't get offered Maestro is almost certainly because the first
leg of the flight you were booking was 'to' the UK and not 'from'. If
you start your journey from the Continent, the Ryanair computer
assumes you're a foreigner and doesn't offer Maestro, and indeed
doesn't offer sterling prices either. This infuriates me too because
I book quite a few single flights starting in Germany and have to pay
the even more inflated VISA card service charges that Ryanair gets
away with.
pete