This little number is a real enigma: this is how we THINK it played out, but we aren't sure. The basic is a very elegant dress coat early 1960s that has been adapted & psychedelic lining added at some point during the later 60s to the hooded gilet bolero; we think Maybe Emily raided mummy's wardrobe & got busy with sewing machine, or mummy fancied to 'take a trip' herself! Either way the front is now mini skirt coat cut (ie opens from a slight 'Regency' Empire line) so you'd need a mini for under it. BUT it may have been done much more recently with the psychedelia revival....as I have seen retro fabrics similar to the lining. The coat dress & gilet are definitely original 1960s however.
So....
Emily tries but misunderstands
She's often inclined to borrow somebody's dreams 'til tomorrow
There is no other day
Let's try it another way
You'll lose your mind and play
Free games for May
See Emily play
went the Pink Floyd number, written allegedly about the Honourable Emily Young, seemed a fitting inspiration for the garment shoot/video.
Kensington posh flirts with the psychedelia scene is what it says to me but has a versatile charm because of it: could look very now with the new
psychedelia scene, but also worn without the gilet & hood very elegant but a bit naughty, period. 
Please note this is home made/adapted, thus was made for someone clearly of a svelte figure so you need to be around a size UK 6 or smaller to 
get away with it. I'm a size 8 atm and it's  now iust a bit tight but was fine when I was 6. A UK 4 would be fine too, but you wouldn't want to be too tall or too busty.