Congrats! Great find!
I used to be a huge Blackstar fan and from what I remember, it looks like one from the "Metal" line - so this would be an HT Metal 100 if that's the case. IIRC, it was limited to only a 2-3 year run and they had 5, 20, 50(60?) & 100 Watters and had cosmetic changes several times in the run... but they do/did weird stuff so I might be wildly wrong. Or someone could have pulled the facade and replaced it with the metal grill.
The "TVP" stands for "True Valve Power" and I always thought that was their modeler lines - but like you said that's clearly not a modeler.
My wife has an ID:60 TVP and it rips - especially with an SD-1 in front. No matter what it is, a 100 watt head that works for $150? Score! Wish the Pawn shops around here had deals like that... they're all busy trying to sell $300 beat up guitars for $450...
If you're on Facebook, there's a
Blackstar Amp Appreciation group and a woman named Michelle Taylor in it who is a walking Blackstar encyclopedia. Killer guitar player too. She could identify this for you, if you're curious.