Jeez.........Some proper info:

1) A seat is not necessary and unless your child is absolutely enormous, he/she should be able to use the Britax seat, rather than the bassinet. Even if this is NOT the case as someone says above, you will be able to use another seat.

2) Unless your seat is CAA approved, hich most bought outside the UK ARE NOT, any car seat that you bring with you will be a useless weight for you to carry and NOT use. BA and VS FA's are incredibly vigilant about this. So forget it. Similarly the belt loop which the above poster refers to is also a CAA thing.

3) SwissTony, Unless something has changed in the last 2-3 years BA has ALWAYS provided child meals, automatically for that matter. Yes, they are often crap but they are provided. I only base this on the 24 or so flights I made on BA when my child was an infant. Perhaps Economy is different, I don;t know.