I have heard this.  For a while I thought it was one of those myths, but yea, it's true.  Am I right in thinking that it was something to do with a video or a news program or something and he was the actor they hired?

This was a publicity stunt.

Reg was famous on tv in 'The Rag Trade' when he was invited by Barclays Bank to unveil the very first cash machine to be installed at any of their UK branches (just in the same way that celebrities were asked to open new supermarkets back in those days).

And as it happened, no other bank had them then. So it was the first ever cash machine in the UK.

As part of the public appearance, he actually used the machine in order to demonstrate how it worked. He wasn't just passing and in need of cash...