Reading between the lines of your description, I think my little brother had the same model.
The paint is blue/white fade, but it would originally have had a red and yellow panel sticker covering the faded sections to give the impression of sharp colour transitions. The bike would originally have come with a drop bar.
edit: like this:
http://www.flickr.com/photos/jonathanmr ... 017390060/
The indexed shifter is probably six-speed (five clicks for six positions) and would have been matched to a Shimano Light Action rear derailleur.
Dawes tended to recycle their model names, and I've seen a Celeste from a much earlier period - fillet brazed with chromed decorative head tube rings. Yours dates from about 1987-88. You'll probably find a date code on the Weinmann brakes.
Calmes dans le demi-jour
Que les branches hautes font,
Pénétrons bien notre amour
De ce silence profond.