Wayne I have a large B&Q not far away that is useful for small quantity metal products. It beats wasting half a day driving into the city to queue up at a trade counter where they don't want to sell diddley quantities to the public anyway.
Besides if you overbuy in B&Q you can take it back for a refund. But I have learnt not to do that, as excess bits will always be needed for something eventually. You're too young to know about this, but some of us get 10% off on Wednesdays
With the exception of brake pipes, I also get my plumbing there.