Nutloose, all of the categories are either 'racial origin' or colour based at the start e.g. white English etc. I know what you mean though; the armed forces are supposed to be colour-blind when recruiting/promoting, but are also forced to pigeon-hole by race/colour when recording details of applicants, so both ends working against the middle in some ways.
I think just examining what makes the forces attract people by looking at what the forces have to offer, will only ever give an incomplete answer. You start getting a clearer picture when you compare the services with other occupations and parts of the public sector (NHS etc.). My own view is that it might be better to assume that the services will always be seen by most as lacking in appeal compared to the professions and quite a few other leading industries/areas of the public sector. With that in mind, the service offering should consider a genuinely compelling and beneficial counterpart to any time in uniform, probably along the lines of paying for a degree or other genuine professional qualification, open to all ranks, that can be taken up after a minimum engagement period. This would take quite a lot of investment, rather than the somewhat half-hearted attempt (with limited scope) at the moment, but most ambitious people from ethnic minorities (and whites as it happens) pretty much agree that a good education is invaluable. It would take quite a bit of money and change in the culture to convert the services to having such a 'two-part' offering, but I think it would at least put the armed forces in a bit of better place on a list of career choices.