I think it's a universal problem.
The supply house I use most is pretty good most of time, and the best priced around here. But sometimes I go in and they're out of stock of some garden-variety item, such as 4mm T&E cable (imagine your place had no stock of 10-2 Romex).
Sometimes it can take two weeks to get something sent up from their main depot in London, about 125 miles away, so I have to resort to visiting B&Q (like Home Depot).
