FINALLY - SOLUTION FOUND !!!
Everyone was / is talking permissions - and finally found something at
- On PC - right click harddrive you want to access
- Select properties
- Select security tab
- Click advanced
- Click change permissions
- Click add
- Type Guest in the object name box
- Click check name (to make sure ok)
- Click OK
- Tick allow full control
- Click ok
- Click apply
- Click continue on any error messages.
Now from iMac - get to "Connect to Server" (CMD+K) and enter normal smb:// pathname (to access my photos drive is use smb://office-pc/photos
Enter Windows PC Username/Password at prompt - and presto - all now accessible
I hope this helps others out too.