This is the closest recipe for an authentic Japanese yakisoba sauce we've seen, using only UK-bought items. It's essentially a combination of Worcester sauce, tomato ketchup and oyster sauce, none of which are anywhere near Japanese! In fact, Worcester sauce is a truly British sauce originally from Worcester, produced in 1837. By adding a little bit of soy sauce to it, it it instantly adopts a Japanese flavour. We've tried it and it works, so don't despair - enjoy the true taste of yakisoba fried noodles made with UK ingredients.
See Deepseafish's recipe for Home Made Fried Noodles (Yaki Soba) here.