thanks for your input.
this was one of several attempts to sort this out.
Ray helped me with the update page.
i now have insert and update working successfully
i (sort of) have delete working, in that i can delete the row from the primary table and the rows from the related table.
what i can't do is display the rows with the appropriate checkboxes checked (like the update page), if i do this, the delete doesn't work in the related table.
difficult to explain, i will work on it some more and send a link when i get time.