I believe that if you use a 'chip' to convert the km reading to miles there is an opportunity to 'clock' (reduce) the reading.
It is important to review the auction sheet prior to purchase, as that certificate states the kilometres travelled prior to export.
There is, of course, additional travel after export; potentially from UK dock delivery to wherever (although many are trucked); and this should be considered.
My Alphie was clocked but, fortunately, only by a small amount.
Potential buyers should be aware there are 'Specialist Alphard Dealers' and 'Dealers who deal in Alphards'
Generally, there is a difference in quality and service provided by each of these categories.
Having a new 'chip' fitted (at any time) is an option for Peter and Liz; assuming there is no other cause.
This could be an inexpensive repair solution that any reputable Specialist Alphard Dealer could perform for you.
To be clear, absolutely clear, I am not suggesting, or promoting, 'clocking'.