WoodlandsCamper said:
Strange in this day and age not to take plastic.

I also see from their website that you need to send a stamped addressed envelope in order to get a receipt if paying in advance. A very archaic financial setup.
Are you on the same page:
http://www.diamondpark.co.uk/payments.html
Lots of plastic options and PayPal which is the contemporary method of transactional payment in the ether of electronics / inter web etc. Possibly a shrewd move as no fees to buyers on cleared/available funds. Or maybe they prefer cash for nefarious reasons to fuel illegal activities and terrorism as everyone is at it, apparently
Perhaps sae etc is to cater for the non connected generation more akin to the CC / camc / wotever that they wish to entice away from the yoof who will be flooding those sites on their adventures in their motorhomes
