I can understand your aprehension, but really, it's nothing to worry about. If you 'do' anything profesionally, be it a chef, a musician, a doctor, what ever, then you will find that sometimes someone else does what you do, either to you or for you.
Because of the chef progs, especially Mr Ramsey, it's easy to imagine that any chef is looking and judging with a critical eye. He's more likely thinking how nice it is to have a day off from cooking, and let someone else do it! I really wouldn't worry - it's a social event not an exam, and if he is a lovely guy, he'll be aware of what you feel, and try not to let you bother too much.
You don't have to be a chef to be critical of someone's cooking - if he were boorish enough to be rude, don't invite him again, but I am sure he enjoyed what you did, and didn't give it a second thought from the 'quality and presentation' point of view.