Originally Posted by JustTheOne

Contact YouFirst beforehand and ask them for the full menu for your flight(s) - they will send you a PDF of the actual menu, so you'll see everything that will be served (not just the pre-order options listed on MMB) and can work out an eating strategy.

For example, the new amuse bouche option always appears to have one non-meat/fish option out of the three served, so you could just have that one and ignore the other two if you're ok to do that (they are served in separate dishes). There's always a veggie main for the larger meal, and usually a veggie option for the second meal (although not always). It depends on the flight destination and timing, but I usually find this strategy works for me and I don't have to order a special meal. Afternoon tea is probably going to be the only instance where this might not work, but again knowing the menu in advance means you'll be prepared for this.

The only risk would be with BA's woeful under-catering, but as veggie options always seem to be the last to go anyway, this probably wouldn't be much of an issue!