BA in CAI is OK but for anything out of the ordinary they will ask London for approval. That takes time when the London contact is unavailable. I waited three days while London thought about open tickets with transits indicated to comply with the rules regarding stopovers. They never did respond but the CAI agent finally took the initiative and wrote the ticket the way I requested -- the day before I was scheduled to arrive in CAI. Give yourself plenty of time to work out any conflicts.