Resetting Service reminder for Gen5 Outback - how? Or not possible DIY?

[Justin Time]

My 2020 Gen5 had it's first Service in December 2021, when it had clocked up about 6000 miles (the service interval is every 12 months or 12,000 miles whichever comes first).  The dealership reset the service reminder to correctly read December 2022, but they left the mileage at 12,000! It should have been reset to 6,000 + 12000 = 18,000.  Consequently, it has just recorded a total of 12000 miles and I'm being 'reminded' by the incar computer to take it for a service, even though it's only added another 6000 miles since the last service in December 2021.

Is there a DIY way of fixing this error so it reads not only the correct service due date, but also the correct mileage the next service is due on?

Also, it's a bit disappointing that unlike my last car (a Skoda) which gave a 1000 miles warning count down if the mileage for servicing was approaching, or gave a 50 days countdown warning it the service anniversary date was going to be reached first before the mileage target. That way there was plenty of time to organise the service, if I'd inadvertently not had that requirement on my mind (rarely 🙂 !), so no surprises.