well that was just too weird, after driving 20 mins back to my base I got out and suddenly everything is back to normal. It wasn't my imagination as I'd checked several times before reporting, I couldn't interact with the spark plug & battery or the inside of the car inventory as there was nothing being displayed in the "Vicinity" I'd just found a train and was unable to loot it as I couldn't place anything in the Olga as the inventory wasn't there. I then drove home to find it now working.