Clutch master cylinders ?

I had a problem with the girling master cylinder in my SGT 40, it leaked from the push rod therefore a seal was faulty, I found out that the supplier being builder solutions actually sold alternative manufacturers not girling. Never the less I got another one thinking is was a one off crappy one but now the second one is leaking from the seal area.
I stripped it and found very fine particles of ally in the push rod area and weirdly the dot 5.1 fluid was black only in that area as if the black seal was breaking up.
Bloody weird.
The push rod is dead straight ,I know the fluid is new, clear and free of any crap so it must be the cylinder at fault again.
I'm going to get a genuine Girling one tomorrow and fit this.
Has anyone had this problem. ?
The type is Clutch cylinder with integral reservoir . 750