Alternative battery set for PlayMobil R/C diesel

Tidying out a cupboard yesterday I found a nice battery recharger - which can do up to six AA's at a time.  I have 10+ rechargable batteries which I use for my digital cameras, which are not all needed for that purpose now so they can be re-used to power  my PlayMobil R/C diesel.

Battery pack taken out; needs 6 AA batteries - currently using some non-rechargable Duracell ones

 6 batteries re-charged; good little charger with progress display ....

  into the diesel's battery pack

 it works (well of course 😁 it would, doh !)..

so I now have a backup set of batteries available for the running season. The Duracell ones still have some life in them so I'll use them up first and then start using the re-chargable ones.