Thanks for your replies.
I've checked out the link that tugg gave (cherrs tugg!

) it does helps, but the main thing I'm concerned about is the swimming.
The story is - I joined the Army (infantry) at 18 and left after completing the minimum service. Now I'm 25 and would like to go back before I get too old. But I quite like the look of the RN or RM.
I have been working on my fitness to get back into shape. I've got the 2.4km run under 8 and a half minutes and feel pretty confident about the other parts of the tests....but I'm not really a brilliant swimmer
I've been going every morning to improve, but I wondered if there is a minimum standard, so I can set a goal/something to aim for etc?