Think of it this way. There are several hundred thousand parts lines held in stock in the UK and Belgium. Multiply those numbers of lines Worldwide and you can understand that most of those are made by outside suppliers making them on behalf of Toyota. Those other manufacturers will also be making parts for Toyota, Nissan, Mitsubishi and any number of other car manufacturers. From time to time there will be occasions when those suppliers are unable to meet demand, maybe through planned shut downs, holiday periods, shortage of raw materials or any number of unplanned delays. Parts demands are very carefully monitored, if as the Fox suggests, this part fails regularly, then you can be assured Toyota will make them to supply demand, after all, they make money from supplying goods, they make nothing if they cannot get hold of those parts I am sure this is one of those temporary glitches we get from time to time, Toyota have a 96% first time pick rate, the highest in the industry, sadly your part is one of the 4% that cannot be supplied from stock