You could do far worse than one of the Trek FX series hybrids. They start at £300, lifetime frame warranty and a five year warranty on the Bontrager parts where fitted, such as rims, stems, handlebars etc. The 7.2FX has a cassette rear hub with 24 gears, sealed bottom bracket etc., which will provide good durability for commuting regulary, price £400.
Also consider the GT Traffic and Mongoose Crossway bikes. All of these bikes have eyelets to allow fitment of mudguards and racks. If you want a bike with all of these already fitted, the Trek T30 costs £350, has 21 gears, cassette hub, mudguards, rack, stand, full chainguard, adj stem, fitted as standard. It looks a bit more old fashioned but is a good work horse, been using them as hire bikes for 3 years, and they have been super reliable..