Norge 8Valve Fork Seals

My 8 Valve Norge has started to lose fork oil through the right hand fork leg seal. The bike has only covered 5000km. I notice the service book recommends that the seals be replaced every 10000km so maybe I have just been unlucky. Does anyone know the seal size so that I can purchase them before stripping the forks? Is there any advice about seal make or type that may help in having them last a little longer than 10000km?

Hi all, I have found the sizes in the prats book. they are 45id X 58od X 11wide.