I don't think it's Candi Staton. I know she made the record, but I don't think it's her in the advert. The person singing is so out of tune and sounds nothing like the original.
Maybe it is an updated or live version by Candi- she is in her seventies now so her voice will have changed in quality. It'd be a shame to have ruined a great track though
True, but old habits die hard. How often do people still talk about Inland Revenue, The Water Board, The Gas Board, etc. Last week I found myself congratulating one of my students from last year on passing her 'O' level Maths