It is one ticket for the whole journey.

there is not really a stopover, however, I have to wait overnight for the next flight, around 23hours.

Ba seemed to think the bags would be check straight through.

the cx part of the journey states 3 bags, but then so does the ba connection to lhr form London, so it could just be wrong.

thanks all for your help.

I think I will just take the 4 bags and fight it out at the airport if I need to.