Mixture, thank you for your generous words of encouragement. I know that if I crack this, I will be quite satisfied with myself. On the face of it, it does seem a simple task but I am on unfamiliar ground.
I have an overall picture of the set-up now and roughly know where the 'fiddly bits' hang out. The next issue to solve is the password one. I'm sure the Mac is connecting to the Tosh and is seeing the workgroup but it is requesting a password. I'm not sure what password though as I don't recall setting a password for the workgroup when it was created. My Mac account password doesn't seem to work so I'll try and retrace my steps later. It is nice to know I am welcome back here if I really get stuck. I'll also take shots of any windows and post these as well.
Gertrude the Wombat, when I was a pre-press chap in print with Mac and Windows servers all over the shop connected to a myriad of devices I relied on Magic because frankly I didn't have much of a clue as to how it all fitted together! I realise now that I should have taken more notice of the networking engineers, I could have learned a lot from them.
Thanks again for responses.