The error appeared a few days ago. I hoped it would sort itself out but no such luck. I ventured down to the local indy and they put it on their computer thing. A Mass Flow sensor issue was quickly diagnosed and by luck, they had one in stock and I was on my way within 10 minutes. Top service and the car has been fine ever since!

Anyone else had the Restricted Performance error and if so, what was the problem?

Yes, and the causes can be many. In my case it was a split intake manifold that meant as soon as you hit more than 2krpm it threw a hissy fit and red triangled me.

The garage did think it may have been the split manifold issue (something else to look forward to) but as I mentioned, got away lightly this time!