Probably if it just says Victoria & Albert's, it's in the main room as my confirmations have all specified Queen Victoria Room if that's what I booked. I don't think they offer 7 and 10 course menus anymore; it's what the chef feels like doing and can be between 9 and 12 courses. The chef now chooses your menu based on your preferences or allergies/intolerances which they check on about a week prior. I can't eat seafood, spinach or sunflower oil and they always not only customize my menu to remove all seafood but last time one of the breads served between courses had sunflower oil in it so they made a different one for me. They also advised me when I couldn't try any of DH's courses because of seafood in it (not that he'd have let me anyway but it was nice that they warned me).
Having eaten there several times, I would recommend, unless you absolutely cannot eat something - like allergies, intolerances, literally makes you sick - that you let the chef do his magic rather than specifying things you just don't really like. In the hands of a professional chef at that level, you may be surprised at what you actually enjoy. Like the PP's GD, I absolutely hate, hate, hate mushrooms of any type - the taste, the texture, the smell - ugh. But the first time I ate at V&A, I ended up having a mushroom pasta and it's one of my most favourite food memories (an earthy, rich, creamy little bowl of deliciousness that my tongue still remembers). I still won't eat mushrooms anywhere else but I will eat whatever chef chooses at V&A as long as I'm not allergic to it.