Sorry, but I find it just a little bit weird that this woman apparently related to you via your father, that to the best of your knowledge , rarely, if ever bothered to spend time with your dad, decides that she must be allowed to dictate who you should be allowed to invite to an occasion that will already difficult for you.
You will no doubt be reminiscing about your dad at the meal after, along with talking about family things that she will have no idea about!
I would be tempted to ask her straight out just why she thinks that she wants to be there anyway?
She already knows that you are paying for the meal, how about saying that unfortunately, things have changed and all of your guests will be paying for their own meals and see what her reaction is.
If she gets shirty again, just say that because of her attitude, that you find really upsetting after the recent loss of your much loved dad, and that you would rather she wasn't present at all.
To be really irritated by chefs over praising their own food?



