It's possible to pay by three different ways for a portrait:-
You can use Paypal even if you don't have an account with them. It accepts all the major credit and debit cards, and is a secure online transaction service. (Unfortunately it's not possible for me to take your credit card details over the phone, this needs to be done via Paypal).
Please send your cheque with your order form. I don't cash cheques until a week after posting the work. I ask for the full amount to begin with, and offer a full refund if for any reason you're not happy with the work.
If you'd prefer to pay this way, please contact me and I'll send you the BACS details for arranging payment.