I thought that information titled 're-learning in a transmitter' (from Risco site Frequently Asked Questions) might get me away - It seemed to say it is accomplished by setting and triggering the satellite alarm. Alas this has locked out alltogether the 595 master control system requiring an Anti-code to be discovered. This anti code obstacle seems to disappear when I carry out the following procedure.
Enter engineer mode
Step through all functions but do nothing
Exit engineer mode
These steps together with the replacement transmitter battery fitted appears to have restore the system to normal functionality (with the satellite tamper alarm cancelled).
If anyone can help with Risco engineer information so that I do not have to stumble on solutions like this I would appreciate it as I have developments in mind for my security system which may cause problems with the 595 which are not so easily worked around with 'blind' keypad operations.