To update my situation, the seller of Elrogs changed his tune when challenged and basically said he used this pair as well and sold me working tubes. He didn't address the fact that he said both are new replacements while selling, which wasn't true. To be honest the tubes worked for 20h so hmmm ... he did in fact sold working tubes ... but he also lied and didn't provide the measurement sheets. He also wasn't kind enough to offer any compensation for my loss. I would at least offer a partial refund in his position but he has no obligation to, so he did not.
Anyway, I will try to get a new tube paired, my wallet will be 790 euro lighter but at least I will get the return shipping in that price ... hopefully.
Btw. I can't say I didn't think about WE giving 5 year extended warranty ... but I don't know if current production WE would sound as good to me. No doubt, if my last encounter is to go by, I think the Elrog sound in itself is worth the asking price ... but if I had a tube failure after 1,5 - 2 years and be left in the same situation I am now I wouldn't be too happy about it ... never the less it is what it is. At least I will have a year warranty for 1 of the tubes
The moral of this story is, buy that kinda tubes new. Also I really wish there was an extended warranty for Elrogs.