Just to echo the above, the customer service from BAH is excellent. We had a flight cancelled for a five day Sardinia holiday and when I called them up to see what the options were, it seemed we could do pretty much what we wanted, when. We don’t like very early flights so they were happy to go through a whole list of dates to get the right match (it was CE and an R fare).

I was quite impressed. Just my experience so others may have different views.