This is the sort of claim that should be dealt with as a serious claim, probably using a solicitor in order that it receives proper attention at BA. I think that you are looking at some real money here, not least because BA should be really concerend about the publicity. Once you get to a figure, you might then want to raise the alternative of miles, but I certainly would not start out down that route as it would not look as though you are taking it sufficiently seriously.

I am sure that the crew will have had to fill in an accident report and that this will be reviewed by the relevant authority (CAA, Health and Safety ??) so it should already be well documented within BA and they should be expecting your letter.