Since it is for sale on several commercial sites I think it is unlikely you will find such a source. They usually keep things pretty much under control for current products, from what I have seen. It's like looking for software cracks. Usually you only find them for old versions, that's my experience anyway. Illegal file sharing may be an avenue if you want to risk the amount of viruses that are spread that way. Even that looks like it may be getting clamped down on. I saw one of the big Torrent sites got sued for a kagillion dollars last week or something. 20 quid doesn't seem like a lot to pay for something like that.