well my own manual is very clear about it and it has mixing guidelines there as well, pages 22-23, 2006 edition as said. therefore, it any of my colleagues who have been trained in the last 3 years claims that Lesmills does not allow mixing, then I can only assume that they have not actually read their manuals. (if the club doesn't allow it, it's a different story, although I don't personally believe it should be up to the clubs to decide). Was asking as some colleagues claimed that this is a recent change and their manuals told to keep the same for 3 months. But as it was explained above, I can assume they haven't read their manuals either..
No animals were harmed in posting this message, although the yorkshire terrier next door is living on borrowed time, let me tell you.