Triumph 'single' main engine parts are hard to find, but items such as pistons, valves, guides, crank bearings etc shouldn't be a problem. Lots of other parts were carried over to post war bikes and can be obtained from dealers such as Trisupply in your home county or Ace Classics in London. John Brewster makes fork spindles/bushes and head stock bearings. I'm also in Dorset (Poole) and have a 3SW and 3HW in my collection. I'm also currently restoring a 5SW for a friend. Give me shout if you want to pop in. Ron