I don't mention. This has long been the major booksellers and stationers in Cambridge. They do accounts, have a web entry , and you can email orders to them. Basic stuff, I prefer Heffers but Staples is easier to get to if I'm in the car. Pretty much anything you can fold or tie, in fact.
Sheet metal seems expensive, but apparently it is everywhere.
The usual sort of DIY supermarket, and reasonably good for what it is. Motor vehicles See my Cambridgeshire Land Rover contacts page. I reckon this is the best of the local cycle shops, although a bit expensive compared with some. This is also good, and stocks some more old-fashioned stuff than Howes, useful for doing up old or bizarre bikes. Wide range of stuff, both Asian and non-Asian.