After all that and a check up at Brand Hatch they couldn't find any obvious leaks at front or rear which is reassuring but leaves a small element of doubt. I'll just have to keep driving the car and see if the smells reoccur. Maybe it was just overflow oil dripping on the hot crank case and given off a petroleum like smell or maybe I just drove through a puddle of fuel and that introduced the paranoia. Anyway no excuse not to drive the car now so I will.
