Just found a pair of "Skinny" pants for my son's 11th Doctor outfit.
I made the bow tie, he has a red one too, and the jacket. Just need to get some "braces" for him (As they call it in the UK) and he is set. Still looking for boots. For a six year old I don't want to spent too much as he will grow out of them soon. Before Gallifrey next year by my luck.