As far as I know, it also include EL3N as they are not in the manual. So there's not a lot of people with warranty anyway in this thread.
For people looking for cheap conventional tubes, I can recommend FOTON 6N8S (pre 1966 thanks to @hpamdr for the tip) and TungSol 6080 (a bit hard to find).
True the EL3N is not on the "approved" list, vince...but as I have asked Lukasz if there would likely be any major problems using the EL3N, and he thought there wouldn't, I feel we are on fairly safe ground with this tube. And so this gives us a fair bit of reassurance, methinks..