That's good to know Sandy, I will be going for the quarterly option to maximise the Forums share.I think each d/d payment has an amount of fee. Got a feeling it's the same regardless of amount. So, if that's the case a quarterly payment of £15 would have less in fees than three one off payments of £5. I don't think one off standalone payments have a fee.
Still, the option is there now, hopefully it will be useful.