Spooky goings on with my central car locking?

I have a 2 year old Toyota Verso and have never had a problem with the key operated central locking. Two days ago I parked at an address in East Sus to find that the central locking would not work at all and I had to use the emergency key to lock the car. When I returned to the car, the central locking was still out, I unlocked the car using the key which set off the alarm. This stopped after a minute or so and I was able to drive off. The central locking then continued to operate normally. Today I returned to the exact spot I had parked at before only to find the central locking refused to function yet again. On leaving the area, the central locking operated normally. I noticed that I had parked on a freshly remade section of the road where clearly road works had been done and I wondered if anything underground, perhaps electrical, could have caused this? All ideas welcome ! Thanks ...