theworld,

I am a pure vegetarian too, and have had a combination of the experiences mentioned above. I recently flew LHR-NBO return twice in J in the last 6 months.

The first time around I did not request a special meal, and was provided with a veggie option both ways.

On my most recent trip, I did request AVML both ways. On the way to NBO, I had a special meal, but on the return, it was just the same veggie dish as one of the options on the menu.

I believe that BA always has one veggie option to certain regions (South Asia, Africa, Middle East), but I don't think this is the case with flights to the Americas.

Hope this helps.