I only just noticed that thread Yvonne. I saw you posted a question about if a Great Dane is crossed with a lab are the puppies Pitties? The answer is absolutely not
To make it confusing the term Pitbull covers a few different breeds and often refers to similar breeds. If you look back in history bulldogs and terriers were crossed to make fighting dogs for entertainment - they would fight in pits and became known as pitbulls. Go through the years with different breedings and distinct breeds emerged. The Staffordshire Bull Terrier was one and the American Pitbull Terrier was another. What is now known as the American pitties were the breed created after lots of breeding to make the best fighters. Now I believe it is this type of dog which is the one banned over here ... Both full bred or a cross of this type.
Because Staffies share a history with pitties it's easy to cross them with other breeds and end up with dogs that look like pitbulls. Technically they are Staffie crosses but if you can't prove they are it's so easy for people to label them as pits of pittie types.
I think that's how it works, it's really complicated but it's something like that, I've no doubt missed out a lot of info, but I'm not a bullbreed person.