I assume you have harnesses and the harness bar fitted.
At my SVA, I was cross-examined for it's strength. I had to call Mark at Marlin to obtain the OD and wall thickness of the tube. The examiner discussed this with his colleagues during a break and it was deemed ok.
At SVA, I put to the examiner, that other cars had passed with the same ORIGINAL Marlin kit...
Like you I argued that it had been accepted else where.
However I was then advised that Robin Hood had tried to pull the same stunt on their kits and challenged the VOSA decision.
It boils down to will the bar hold 3 ton back in the event of heavy duty breaking, my examiner said that as the bar bent under his own strength it was unlikely to hold back the above mentioned weight.
I asked what it would take for him to approve, he said replace the whole thing with 3 point standard harness either static or inertia.
Just cant win with the bar, anyone have a set of 3 points I can borrow till through SVA?