A standing order is a regular monthly payment that you can set up to pay other people, organisations or transfer to other bank accounts. You can amend or cancel the standing order as and when you like. You are in total control and can increase, decrease or cancel payments at anytime. This is St Bart's and Anne's prefered donation option. You can set an amount of giving that is appropriate for you. St Bartholomew's does not take the money, you set up the order to give just the amount you say.
A Direct Debit can only be set up by the organisation to which you're making the payment. Normally, you sign a mandate that gives the company permission to take funds from your account in an agreed way – like a monthly gym membership or your mobile phone bill. It normally confirms who's receiving the payment, the account to be debited, the amount and the dates of the payment. You're protected under the Direct Debit Guarantee scheme so that any amount debited in error is refunded immediately. With a Direct Debit the company may alter the amount that is paid. (They notify you that on a certain date, they will take £xx from your account)