Stud is easy, just buy a length of thread all and cut it up.
Any engineering fixings supplier will supply small quantities
But why BSW, are you rebuilding an old machine?
My local supplier Bapps at Scunthorpe 01724 282112 will supply, I bought a length of 1/4" threaded rod off them and half a dozen nuts, though I can't remember what I bought it for. I still have part of the rod and some of the nuts, though I think the nuts are in my "Farmers Box"
They also have the grubs, though again why BSW together with taps!
They accept card not present as they have sent me bits when I've been working away. I use a lot of imperial/american stuff in my work.
Funny, I bought a chinese barbecue and found the nuts and bolts to be 1/4" BSW

Robin