Hi All,
At the advice of @Roottoot I booked into Victoria Garage (Maud). https://www.victoriagarage-maud.co.uk/
Car was in first thing this morning, and they diagnosed and fixed the rattling noise inside 90 minutes.
I asked them to look at the noise that the car was making when it was idling, reversing, moving forward without accelerating. They discovered that the water bottle retaining strap bolt had fallen off, and the retaining strap was vibrating on the bottle and surrounding area. This was the cause of the rattle. New restraining strap and bolt installed, and now no rattle.
The noise from the wheels area when the car is turned off, as indicated by @ZacDaMan72 and shown also by @chrisluciofg, seems to be normal for the car..... weird but normal!
So warranty work completed, and happy drive home without any annoying rattle!
A word on Victoria Garage (Maud), they were brilliant to deal with. Thanks @Roottoot for the recommendation. They were easy to speak with and seemed really trustworthy. Even cleaned the car for me before returning it to me. If there's no Skoda Inverness garage in the foreseeable, I'll be heading there for servicing from now on. Bit of a trek, but no worse than driving to Perth or Aberdeen!
Many thanks for all your help and advice.
Steve