racedo what you say about pit wheels would be true if there were 400 units to hold stock. In terms of ac spares you miss the point that if a supplier has been allowed to let stock holdings dwindle to 0 based on historic uses and those items take 2-3 years to manufacture that is an expensive error. More embarrassing perhaps, given the general longevity of UK ac is that sometimes the skill sets required to manufacture some items have ~ literally ~ died off.