You can purchase one from farnell electronics for around 50p,now's that's cheap as chips.
9800 NVM # 93C46 or redcare equivalent,
Just take extra care not to bend the pins and ensure you fit it the right way round,all the info you need is in the engineering manual that is easily found following a google search.just follow the defaulting method and reprogramme as necessary.
As a matter of interest did the engineer remove and refit the NVM?,
Iam not on here to question your engineers work ethics but I would defo get a second opinion because I can't see why the engineer couldent fit or code one up?.Anyway good luck with it
e manno, June 2012