Currently my client is a world user with many legacy interfaces written in RPG (payroll etc) looking to move to ONEWORLD (AS400)
would be happy for any general tips anyone might be able to share in particular I am getting conflicting stories over the need to convert my RPG interfaces to ILE any advice for me??

many thanks

The primary reason to go to ILE would be if you were going to use the
OneWorld business functions to write the data into the JDE files. If the
database server is going to continue to be an AS/400 then you could certainly
continue to have interfaces written in RPG directly updating the JDE files.
This is generally a risky integration method for JDE, unless those interfaces
are writing into one of the JDE batch or EDI interface files and then being
updated to JDE through a JDE batch upload process.