RRS 2006 HSE 2.6

I've been having an interesting problem with my RRS the last couple of days. The road drain blocked up the road for a few days, so I had to drive through about 6 inches of water every day for about a week. All that was cleared about 10 days ago and after that the car drove fine.

Then 2 days ago on a short trip, the brakes and stability warning lights come on amber but the car was driving OK. When I reached the destination, I turned the key off, but the engine kept running. I had to leave it ticking over as it's an automatic so couldn't be stalled, then I drove home. The engine then stopped OK.

The car did pretty much the same thing the next day.

At a guess I'd say that water has got into the electrics somewhere, but can someone suggest where to start looking? Or could a dodgy ignition switch cause this. Thanks.

Is guess at the stop solenoid being iffy.