Sorted :-D It must have been the image I was using. Here's what I did:
1. Installed DirMaster
2. Installed WinVICE
3. Created an empty d81 image in DirMaster and saved it
4. Configured WinVICE to use a 1581 as drive 8
5. Opened the blank d81 in VICE
6. Formatted the blank d81
7. Saved a test BASIC programme
8. Copied the d81 to my Amiga and used the 1581 tool to write the d81 image to the disk
This image then worked in the 1581, and I was able to load the test app and also save a new one to the disk.
Thanks all
--
moto