No - the credit agreement is a “running account credit” agreement - you can find this in the app in the manage tab.
Also - S75 isn’t credit card specific. Theoretically it should apply any time you make a purchase directly using credit - this is lined out in the Consumer Credit Act from 1974. Interestingly - Klarna et al don’t currently offer S75 protection - but from a recent consultation paper it has been suggested that they should.