Today the set up regarding the jumper setting's is like this,
WD set as Master on cable select
Maxtor set as Slave on cable select
(This set up has been tried before, but didn't work then)
I can now see the drive
I also know from past experience with this particular HD, that it's just as likely to disappear at the next reboot
I'd like to thank each and everyone one of you, that has made the effort and very kindly offered their time, help and knowledge.
I'll talk to you the next time it disappears!