The Industry is a bit shambolic.
We have XSB, SB, B, Y, SM, W(omen), M, LM and between all the different brands the sizes are most certainly not uniform.
B3 mentioned in an earlier post the height he needs as a 5'7" batsman is 38cms between instep & central horizontal bolster.
There's the simple solution, give us LENGTHS IN CENTIMETRES, not B's, Y's, M's etc etc.
Waken up manufacturers, sort it out!
Strap lengths are an issue too tho. Pads straps have to be made to accomodate the Chris Hoys of this world. When I get this skinny youth in with the right length of pad but his straps looking like tomato plants I advise a bit of home alteration, cut & sew the velcro. But i doubt anyone's ever done it