I bought this at a local coin show from a dealer because it was cheap. The dealer identified it as "Castile & Leon Henri II novena 1369-79 AD", but several other coins I bought from this same dealer have been mis-identified. I'm just trying to confirm or refute the ID on this one.

There's the castle of Castile on one side and the lion of Leon on the other, so the country ID is pretty certain. on the obverse (castle) side I can read "ENRICVS DEI G.." so it's surely a king Henry (or Enrique, as the Spanish call him). My trouble is, there's three Spanish Henrys in roughly the same period: Henry II (1369-1379), Henry III (1390-1406) and Henry IV (1454-1474). I haven't found any references to a denomination named the "novena"; I assume my coin is a billon denaro or double-denaro. It's very thin, and averaging 18mm across.
My references for pre-1600 Spanish coins are next to nothing, and the only billon coins I've found on the internet where the castle and lion are inside diamond-shaped lozenges are denaros of Henry IV -
Example on Sixbid. The lettering on my coin looks more 1400s than 1300s, too, making me think it's really Henry IV. Can I assume that's what I've got? Can anyone with decent Spanish references help me narrow down the date, find the mintmark etc?
Identified - moved to World Coins forum - SapDon't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis