Hi there Hartmann,
I agree with you. The bottom of the feet are indeed strange, which is one of the reasons why I posted the photo. The only explanation I can think of is that this is some kind of 'standard' large-scale minifig that was customised for the promotion, and received an additional coat of paint. That's just a guess though, but there doesn't appear to be much more information from the posts so far.
I'd actually thought that this thread had gone cold, but I must thank whoever wrote and posted the front page article asking for further information, and to everyone who has offered their thoughts so far. I've showed the article to my brother and tried to glean some more info from him about when he bought it. As far as we can both remember, I pointed it out to him as being on display in the window of a rather ordinary newsagents where he was living at the time. When he enquired about it and made the owner an offer, the story went something along the lines of a toy rep (I'm presuming it must have been a Lego rep) had left it with the owner as a promotional item, as part of an attempt by the shop owner to branch out into toy sales. The fact that it really was an average shop in an average town was probably why the venture was never really a success, and when my brother bought it, the shop owner was in the process of closing down that particular side of the business. It was around 2003 when he bought it, which would appear to be contemporary with the date mentioned in the article.
Anyway, thanks again!