April1930s shoppe has everything FW and 301s. I like no shipping charges. I've purchased bobbins, a bobbin winder wheel, and several special feet, but your FW is straight shank so you can use your regular short shank attachments. Her husband repairs FWs so they make sure they reproduction parts are to good standards.
http://www.april1930s.com/

Thanks for all the help.Good to know it won't be a problem. I think I'll start with local shops before trying online: otherwise, being in the UK, I'm likely to have to pay postage from the States.

Thanks for the link!