If BA win then it is highly likely there would be another ballot. There would need to be a 7 day notice period to BA that this would be taking place, followed by a 21 day ballot period at the end if which the ballot result would be announced. If there was a mandate for IA then the union has to give BA 14 day notice of any planned IA.

If BA fail, then there is just the 14 day notice period as the ballot result stands.

All the above is my understanding and should anyone know the law in more detail, please ammend the above.