As I read it, the restaurant chain purchased 'government stamped' glasses (which is what all licensed premises are required to use anyway - i.e. they display the crown mark, shown here:
https://tinyurl.com/ybyoajpp ) but it turned out that the
manufacturer was at fault, in that the glasses didn't actually meet the legal standard.
I've purchased 'stamped' pint glasses myself (when I ran a sports club bar) and it would never have occurred to me to fill a glass with water and then carefully empty it into a laboratory-standard measuring flask in order to check that it really did hold a full pint. Just like everyone else (including the restaurant chain) I took it on trust that 'stamped' glasses always hold the correct quantity.
So I can't see any point in naming the restaurant chain. It would make more sense to investigate the big pub chains who refuse to use 'lined' glasses, rather than 'brim measure' ones, which frequently results in a short pint. Nearly all (nominal) 'pints' poured served in 'brim measure' glasses are at least 5% less than a full pint (whereas the error in the Birmingham case was only 1.4%)