I saw all single tanks. Jacket BCs. The deco reg hose is configured very odd around the hose retainer in one photo. Cross body configuration of deco bottle rather than on one side.
From what I can find online this doesn't violate TDI standards. Here's what I find in the TDI standards for Heliotrox available on the TDI website
"1. Primary cylinder(s); cylinder volume appropriate for planned dive and
student gas consumption
2. Decompression mix cylinder(s)
3. Cylinder volume appropriate for the planned dive and student gas
consumption with submersible pressure gauge
...
7. Primary and alternate 2nd stage required on all primary cylinders"
So a single tank of appropriate volume and any type of alternate appear to meet the standard. The depth and instructor to student ratio (Assuming only one instructor) appear to be clear violations though.
"A maximum of 4 students per instructor"
"not exceeding a maximum depth of 45 metres / 150 feet"