The message from Andy Wade contains these words:
I am stumped for a local MK suppler. Of the 2 major wholesalers locally CEF do not do MK and Edmundsons don't want even their on-line catalogue sullied by a diyers dirty boots.
I have just about decided to go for the MK one with a spare busbar (only an extra £2.49) in case the unit comes with the busbar already split.