The missus took the "shopping trolly" on a longish trip recently and came back complaining about vibration from the wheels at 130 km/h. She even stopped at a tyre dealer and had the wheel balance checked. The tyres were nearly due for replacement but were still legal, I had thought to change them after next winter when the winter tyres come off.
When she got back I took the car to the dealer. In the end they decided it was the tyres and changed them for new ones. Problem resolved.