Veritas R8 alarm query?

Hi, my alarm has been installed for 15 years and have had no problems. The installing company is now defunct. I decided to replace the RKP as the old ones keys were worn showing the 4 digit code. This seems to have gone OK but my front and back door which used to chime when opened now do not. I downloaded the manual and was tring to go through the different programmes but have hit the following problem. The manual tells me to enter the engineers code which the default is 1234 and them press the prog button. When I do this I get an error bleep and it does not go into programme mode. It shows that if you press the engineers code the unset light flashes and this does so I am happy the code has not been changed. Just to be on the safe side I have tried a number of combination of other 4 digits numbers and none of them make the unset light flash.

So in essence, I cannot get into prog mode to make changes to the current settings.

Anyone with any ideas.