What a FAB dress !
"Dolly Rocker... It's called Dolly Rocker... It's an old make of dress...
Well, months old, you know.. that sort of thing..."
So opened Syd Barrett of Pink Floyd song 'Dollyrocker' , recorded in 1970 but not released until 1988 on the Opel album. 
And if any Dollyrockers dress epitomized Psychedelia that may have inspired Syd's song, it's this one! Not so many makes of dress that inspired a song, by such a legend at that. More about that later but first for some details about this specific dress.
It is a UK size 12, though marked a 14 vintage sizing was smaller. I am a size UK 8, so it may fit a UK 10 too it's a little roomy for me but I have not pinned it. It is in a nice quality satin, beautiful vibrant print. It is absolutely immaculate like new. It has a side leg split on one side, to mid thigh.
The dress has a back zip,  scoop neck, and flared sleeves with a cuff split, and is lined in the sleeves and the bust area. Unlined the lower part of the dress. The dress is so immaculate I don;t think it has ever been worn tbh. It is like new, and it is only when you see the sizing, lack of care labels (apart from one which says hand wash), and the factory paper perforated style number label (that is the only sign of age with seamstress pencil signature faded to point of illegibility) of which both parts remain, that makes one date it as an original Dollyrockers. The print is pristine and vibrant, with psychedelia vibes with fuchsia pink, lime green yellow and turquoise. I have seen the same design in another print, which dates from the late 1960s. 
Difficult to date....could be any time from 1967 as before that Dollyrockers were doing Mod dresses, and had Pattie Boyd wife of Beatle George Harrison modelling for them. But they quickly started producing psychedelic designs with the advent of the Dandy Mods and psychedelic scene. Or it could be as late as 1975 when they ceased production. But most of their 1972-75 dresses seem to be of the more prairie peasant dress hippy variety. So I'd say 1967-72. While there was a revival of the label, with reworked pieces, in the early 2000s, the label is different from the 1960s one this piece has, so I don't think it to be a later, piece as they are 'Dolly Rockers London' two separate words on a black label. This has the 'Dollyrockers designed by Sambo Made in England' label in dark pink and orange on a white background. Sambo was the nickname of Samuel Sherman, and prior to the launch of Dollyrockers in 1963/64 , the firm used Sambo as the brand name. 
Samuel Sherman's family had started in the late 19th century with a tailor shop in  Shaftesbury Avenue, and his French mother Rebecca had a boutique on Oxford St soon after, at 399 Oxford St called 'Le Petit Magazin'. Perhaps appropriate for the Art Nouveau prints by Liberty they would eventually partner with for some Dollyrockers prints.  And also of course Psychedelic Art used Art Nouveau influences especially early Pink Floyd and the UF) club on Tottenham Court Rd they played in 1967 regularly as one of the house bands. 
Samuel Sherman had a factory on Old Kent Rd and another in South London (Bermondsey), and their showroom was in Hanover Square a few licks of an ice lolly walk to Liberty across Regent St. 
Speaking of ice lollies, in 1967 when Pink Floyd were playing the legendary UFO club, the 'first ice lolly for girls' FAB, was launched! Lady Penelope was used in early advertising for the lolly and she was quite the fashionista for her day, including wearing Maxi scoop neck dresses! I  And this dress while it may be later, certainly has the feel of that time with the psychedelic colours and Maxi style. The first maxi dresses appeared around 1966/67 after the release of Dr Zhivago and this dress has the 'Empire line' underbust seam of that style. Though they were also a feature right up until the 1970s. Dollyrockers were most definitely a progressive force in the 'Youthquake' boutique movement of the time and would have been among the first to do these psychedelic maxi dresses as they were to do prairie dresses in the 1970s. TV series like Adam Adamant 1966/67 reflected the Regency & Victorian era (including the Art Nouveau typeface) fascination of 'swinging London' & psychedelia too. And while you may read that Maxis weren't seen on catwalks until 1968/69 well don't believe a word of that, Syd Barrett again with finger on the pulse 'Put on a gown, that touches the ground...' See Emily Play was 1967. So, I'm going with the spirit of the age rather than the date of the garment anyway here; it very possibly is early 1970s, but it feels late 1960s. Not that it is full Maxi either, it is long but more to lower calf (I am 5ft 5ins) with heeled boots, would be just above ankle with flats.
So Old Kent Rd to Mayfair & Regent St Oxford st and the Monopoly pieces scissors-thimble-iron I couldn't resist referencing that and the racing car too..... as the Sherman family were very much into their motors, and Simon the son who worked on the Dollyrockers range was a Formula 3 racing driver early 1970s!  Pink Floyd also huge racing car fans and Nick Mason the drummer drove and has a big collection of racing vehicles. Syd Barrett and the band also love their flared sleeves and Regency jackets back in the early days. Psychedelia in the UK wasn't tie dye t shorts and drop out American peacenik culture it had been spawned from Dandy Mods and Dollyrockers were quite a pricey brand, retailing at around £6-£9 or around £120-£180 today's money. By 1968, Dollyrockers designs were sold in D.H. Evans, Dickins and Jones, Peter Robinson, House of Fraser, Rackhams, and John Lewis.
"I know a sweet girl
She done went out and paid for me
Done a sweet girl
After five we went for tea
She seen a Dolly Rocker
She want a girl, she got her
I wanna see her, I know I do
I love you darling, all for you....
All I know, you know, I show you, baby
Through your head push to you, baby
Is a Dolly Rocker
She know what she got her
She seen a Dolly Rocker"
Syd Barrett, 1970 "Dolly Rocker"

"Put on a Gown
That Touches the Ground.....
Put on a gown that touches the ground, ah ooh
Float on a river forever and ever, Emily (Emily)
There is no other day
Let's try it another way
You'll lose your mind and play
See Emily Play"
(See Emily Play, Pink Floyd 1967)
Want to discover more, pause the video down frame by frame and have a read....map of the places mentioned there even should you want a little tourist trek while visiting the West End in your new Dolyrockers dress before a club or a gig of a New Psych band,  or dinner somewhere hip & arty (like Sketch maybe?) ....this is (or was!) Swinging London baby and it's FAB ! So get your Go-go boots and Gab-up ! It's not your seven and sixpence....