Well, instead of the monthly payment and the additional contribution you piss up against the wall why not get out there and shake the tin. Between december and october rather than donate the tenner why not take a few veterans to a hospital appointment or up to Tescos to get the food in, just go round and swing the lamp with them for an hour or even take them out for a tot. That is looking after our own in a personal way and is far more fulfilling than checking a monthly bank statement.
As much as I agree with you I must add that £10 a month towards the RBL is also extremely helpful to individuals such as my father who required financial, legal and health assistance when he left the forces after serving in a number of conflicts.
I agree with Jon Snow that you should be able to celebrate the event in your own personal way.