I never got the sense it was her personal style though - more things that people picked out for her, or things people told her looked good so she went for similar things when she had the choice. Years ago there was a touring exhibition of her dresses - some just seemed to overwhelm her delicate, feminine look (ie big plaids or overly flouncy stuff), especially combined with her signature sporty haircut and harsher 80s makeup. But there were definitely standouts - the one I recall most is the beautiful off the shoulder deep blue gown she wore to the White House and the iconic image of her dancing with John Travolta. With Kate, I really feel like she chooses her own clothes and that she has already defined a style of her own - and that it will continue to evolve, particularly as her role transitions over the years. I see it, but I don't think it's any decree by the Queen or anything so formal. My guess would be that Kate herself takes her role seriously, and especially for the first big tour in awhile, took the time to choose her wardrobe. I wouldn't be surprised if she already knew or even if the Queen mentioned it to her over tea that a bright colour is a good idea in a crowd - I could see the Queen encouraging her, or it could have even been William. I can see her choosing some lower hemlines not because the Queen said anything, but because she knew she'd be photographed coming down the steps of a plane, crouching down to play with George and other children, at a few more somber events, etc. I can also see her still being a bit body conscious since the wedding weight loss and then the baby, so perhaps not being comfortable with showing more leg if they aren't in the shape she'd like or not going with a pencil skirt (which is also not the best choice for getting in and out of vehicles or crouching down to play with children). I could see the Queen weighing in more heavily on the jewels - suggesting pieces that were meaningful or that she thought would be suitable for Kate. As Queen she is caretaker of an extraordinary collection and how it is displayed, so of course she'd have an opinion or two about the tour. And that's where it would make a lot of sense of one of the Queen's people met with Kate to go through the choices and get it sorted out.