Ok, Here it goes, name is Oxalis corymbosa, got the name from my WEED(!) gallery in old Percy Thrower book! Of course it is entirely personal pref as to wether you keep it or not, but if you do decide to keep it, love it alot cos it will end up in every pot, basket or spare piece of ground you possess!!! Anyway, good luck Lottie ;D ;D ;D