For your LHR-YYZ flight, from a month or so before the flight you ought to be able to see the full menu on MMB. You'll actually be able to pre-order your main course from the options, if you wish. When you know the actual choices, it will be easier to make suggestions.

In fact, there's a thread devoted to that topic: http://www.flyertalk.com/forum/briti...ce-thread.html. If you go through that, you'll get a better feel for what might be offered. Another thread often has pictures of actual menus for specific flights in addition to photos of the food itself: http://www.flyertalk.com/forum/briti...ures-here.html.

For the DXB-LHR flight, it may be more difficult to find out in advance what the actual choices will be because that isn't a pre-order route and so I think that the full menu is never shown via MMB. It's possible that someone else will already have flown the route and posted a copy of the menu, but as you're flying at the beginning of a month the chances are relatively slim. Nevertheless, past menus on DXB-LHR flights, if you can find any in those threads, will again give you an idea of what you might actually be offered on that flight.