Aston Martin Virage. Electronic Info Centre problems.

[Geordie McBoyne]

A new DS12778 RTC chip has been fitted.  To facilitate future replacement an IC holder is used.  Everything works, except for one problem, the mileage has jumped 30,000 beyond the original reading!   So we are looking for some method of resetting the reading back to the correct figure. 
The owner of another AM Virage has reported a similar problem.  It's likely the RTC chip is playing up. 
 
Any ideas?

Geordie McBoyne.