If you see a suspicious vehicle (or people) the phone Thames Valley Police on 101.
Make sure you have the vehicle’s
- registration number
- description (make / model / colour )
Thames Valley Police will get a patrol out. They can run the details through their systems and track the vehicle if it is picked up on an Automatic Number Plate Recognition camera.
Also you can use NextDoor to alert your neighbours. https://nextdoor.co.uk/news_feed/
Better to be safe than sorry.