Hi irishstew, bit tricky this without a bit more information, like, have you any idea if they are all meat eaters and can they all eat shellfish?

Assuming that you want to appear as cool as possible and not be seen rushing from kitchen to table every few minutes, I would suggest that you have a cold starter and pre prepared dessert.

Working backwards, a good cheese selection followed by coffee and luxury choccys seems to work well. Creme Brulee can be made well in advance and finished just before serving, or go mad and make Crepe Suzettes which can be prepared in advance and finished in a flash. For mains I would suggest fillet of beef in pastry, or you could use salmon for somthing similiar. Keep the veg even in size and limit it to 3 seasonal types. Remember to have a sauce for you main dish. For starters, either smoked salmon and tiger prawns served on salad bed with home made mayo, or a salad Nicoise made with some fresh tuna. Remember some fresh baked bread. Overall, to look impressive you need to be able to explain how the meal was made, how you sourced the ingredients and prepared each dish. Choose wines with care to fit the occasion, a champagne cocktail or similiar on arrival sets the scene. Flowers, fresh bread, big smile take you time, enjoy! Remember, most people can't or don't cook formal type meals, a bit of care and you will wow them. Hope that helps.