Tonight I have been out in my ford fiesta style 2009 stopped and ate fish and chips in the car engine stopped but radio still on for about 20 minutes and then drove around 10ish miles stopped for about 20ish minutes again with engine off but radio and wipers on. Then finally drove home around 15 miles, when I turned the engine off warning sound and message on message centre flashed engine oil pressure low stop safely and then flashed to power steering malfunction. I restarted the car and message cleared, I did a lap around the block steering felt fine and after stoping and starting the engine a few times the message hasn't reappeared. At no point did any warning lights come on the dash board just this message on the message centre once. Any ideas what this could be? Should I take to the garage? 

You need to check if the car has any codes retained. If not it could just have been a glitch from low battery voltage.