Following this thread on PistonHeads, I've learnt about JIS screw heads. As I posted there, explains why I've been feeling like all my crosshead screwdrivers are wearing out... since I got the Legacy!
I've ordered a single #2 now from Amazon which from what I've seen so far should do most of the jobs on the car; saved me buying a new set of crossheads only to find they're no better than the ones I've got...
Anyway, thought I'd post it up in case it's news/helpful to anyone else here
I didn't find the right solution from the internet.