Raleigh Misty - Roughly How Old ?

I have inherited a Raleigh Misty from the works bikeshed where it has been abandoned, gathering dust and cobwebs and crying softly to itself.

I know its a mixte frame, at least 3 sizes too small for me and not exactly lightweight or desirable but I recon I can rebuild it to fit me better and upgrade a lot of the parts to make a simple tourer/commuter.

The question is how old approx might it be. Features include :-
- Almost showroom new paint job in light to royal blue fade.
- Lugged frame
- Sachs-Huret rear deralier
- 5 speed freewheel, possibly Maillard
- SR 48T single chainring with guard in Black and silver
- 27 x 1 1/4" steel rims with 36 spokes and Michelin tyres
- Steel drop bars 25.4mm clamp, alloy stem, blue fabric tape and non
hooded brake levers
- Chromed steel mudguards

Thanks for any help any one can offer, I'm a glutton for the unsung mass produced brit steel offerings.

Also what was the Male version of this bike called, my brother had one back in the day with black fade to grey colouring and an identical equipment spec.

Cheers

With 27" wheels it's pre 1990. Say 1985 or so?

In small lettering on the frame decals it says 'B4' what if any significance to the model does this have ?

Cheers

Josie Dew had one in her teens - I'm sure she'd answer an email on her website if you ask her... http://www.josiedew.co.uk