I have no idea what "Post-NWOBHM" is but neither of these bands sound like they are from the UK circa '78-'82. I have both CD's and they are also uploaded on youtube in full for anyone else that would like to confirm.
Only until 1982 ?
Well, i go further, a bit further yes.
Otherwise i advise you to check the NWOBHM Encyclopedia (isn't the bible, but so far is the best yet) and see how many releases after 1982 are there featured...
If you start on 1978, i just have to say there are much more NWOBHM in 1984 than on that year.
About the term post-NWOBHM, not many people use it, it is true. It's more used to describe releases after the NWOBHM ended completely (once again - for me it's around 1984) but that still have "traces" in their sound like they were a NWOBHM band.
a good example it's this Seducer demo of 1988
About Dragonsi, if you listen all crap done in 1992, perhaps you could conclude how not updated they were.
I still recall here some opinions about Slander, when Stormspell released it and how much NWOBHM sounding they still were. Never agreed with those opinions but respected it anyway.
Blazon - listen the demo (not yet on M.A. and if it goes by me, it will stay like it is) not the CD.