I did post pics on here when I first pulled it apart, the consensus at the time was that it wasn’t Venom/V-Mach, but I don’t recall any suggestion about whose work it might be. The link to the kit certainly looks similar, though the guide is a one-piece affair in white Delrin.
The rifle has clearly had an eventful life and I expect whoever spent the money on the internal work and external bits isn’t the one who has marked up the barrel with a hammer trying to get the barrel catch unit off and daubing the stock with varnish, likewise clouting the trigger unit....