Apologies for the confusion, the transaction I speak of was for a non-SC product.
The SC Gift Cards were the requested payment rather than PayPal
I have posted this in the 'Other Items' part of the Marketplace?
As a non-SC backer I therefore had to create an account - which was fine & understandable. But there was no information on restrictions applying to these cards on the shop page, in the descriptions, in the support section of the website- a google search now doesn't highlight any issues.
When I need to buy another car I'll be in touch.