Despite being the shy one, Ellie is always the more active in the two girls' relationship, almost embracing their sexuality in a way that Rachel is more reserved over. True, it's not something they really flaunt, as it's just who they are. But when Ellie realised that the UK Pride Flag is basicaly just a pink version of the Union Jack, it seemed an ideal chance to celebrate her love for Rachel and the Queen's Platinum Jubilee.
She just might want to put some clothes on underneath before she goes out to the street party though...
(If I had a 'semi canon' image, I'd put that here - this is canon in that it would happen, but Ellie here is older than she would be this weekend - she's just turned twelve, and she's at least 15-16 here. Ah well. Continuity be damned.)