Well there is a great choice to be honest, if you look at brands like Timex, Sekonda, Accurist and Rotary you can find some great buys which would keep you well within this budget. As well as some of the starter price Tissot watches which give you a Swiss watch for under £100 which is practically unheard of.
To maximise your budget look for a omega swatch on a leather strap as the steel or Gold Plated bracelets inflate the price of the watch and can mean that you are getting a lesser watch because of your budget. The like of the Tissot Desire a mens Tissot watch which with a little bit of a Discount this Tissot mens watch is slap bang on the budget. Alternatively look at the new Classic Dream as well form Tissot if you like your watches a little bit larger.
If you don't mind about not having a Swiss watch, then the choice is even greater you could have the likes of the Rotary GS02580/01 or the GS02622/06 Sekonda offers almost every man's watch within the budgetary constraints but some of the best watches to look out for are the likes of the heavily advertised 3847 and the 3101.