Bosch pump identification??

[zekegti6]

I have 2 pumps here at the moment 1 leaks and the other doesn't the one that leaks has been on a 306 for some time an coded as xud 213

I have a very shiny bosch coded as a xud203 which I've had fitted before and running but not without issues.

What's the difference between xud213 and xud203

Any help would be greatly appreciated as having the refitted Friday and hopefully set up as totally untouched a the moment