Echo, we've plenty of places in MK, halfrauds, wickes, b&q, maplin, sid telfer's in new bradwell or if you're really stuck one of the plumbing places (wolverton/bletchley) or you could try none of the motor factors outlets
urm the St Albans halfords didn't sell it and its a reasonably big store. Try car/bike shops also my local Robert Dyas sold some of them. And if you get really stuck il give you some next time you come to bricketwood