Corsa B 1.0L (2000): Where can I buy an EGR valve housing gasket and pipe gasket?

Haynes manual advises I need both of these parts if I want to remove the EGR valve, clean it, and then re-fit it.Am having problems with the valve sticking, so want to have as go at cleaning it up first before I stump for a new one. via /r/cars http://ift.tt/2sI6Ks4