jetter, you are probably right in that I should try these Gold Lions reissues.
In fact, Kevin of VAC told me that he no longer used any NOS output tubes in his own reference amps. This opinion has a lot of weight. He also said that in his power amps output tubes affected the sound less than driver tubes. I currently have RCA black plates 12AU7 from 50s and like them.
Maybe I should forget about those very expensive Mullards, yeah, but the doubt remains.