Surely you could use your contacts, strap his forward facing car seat into one of your company cars and make out that your recording the next series of Police, Camera, Action.
What happened to the old fashioned ways Strong rope and masking tape....they thrive on it.
Make a den
If you can manage a train journey to London, the Science and Natural History museums are good. Water area for 2-6s in the lower part of the SM and I assume the dinosuars are still in the NH. A bit of a trek but they are free and most kids like a train journey.