Most Available Methylphenidate MR (GP won't prescribe generically)

I've been told by my GP that they won't prescribe generic methylphenidate, and they've instead offered to prescribe any product bioequivalent to Xaggitin XL 36mg. Basically, I have to pick a brand and pray that one is around.

So from Concerta XL, Matoride XL, Xenidate XL, Affenid XL or Delmosart, which one would probably be my best bet? I know it'll vary by location, but any input helps!