Here you mind find some products which will help you repair wood.

Ronseal High Performace Wood Filler
Two part filler can be used to repair any wood, inside or out. It fills to any depth and is dry in just 30 minutes. You can drill, screw or plane it. This filler has superior adhesive qualities, which will last for years even when exposed to harsh weather conditions. 

Ready mix wood filler can be used for any small wood repairs. It'll leave a tough, weatherproof repair that flexes with the movement of your wood, so it won't crack. Available in 6 colours.

Can be used on doors, windows and frames. It will soaks into rotten wood and sets to make it hard again, so you don't need to replace the wood. 

Toupret Wood Filler
Ready to use wood filler for interior and exterior use. Can be applied on any type of wood, including exotic species, chipboard and plywood. Easy to stain or paint. Can be drilled and screwed.

Toupret Wood Repair
Wood filler in powder form. Can be use for repair interior and exterior woods including exotic species, chipboard and plywood. Easy to sand, dries in 3 hours. Can be drilled and screwed.

Polyfilla Woodflex has been especially developed for wood. It is flexible, stainable, water resistant and bonds strongly. Can be used inside and outside.