Certainly, an error on my behalf in not asking for/thinking to get a lounge pass at check in.This should not be the case...QR allows access to partner / 3rd party lounges for Velocity Gold & Plat (unlike e.g. SQ where you only get access to SQ operated lounges). Where possible you should get a lounge invite at check in, if lounge eligibility is not shown on the boarding pass.
However, the whole process did take a bit of discussion at the lounge desk, and they called Qatar check in to see if Virgin platinum was eligible. The answer was no, and so the Qatar contractors at the port did not know about Virgin either.
They also got the Qatar check in staff to remove my VA number and add my QFF number when I played the Qantas platinum card. I think it was a port specific issue if anything (Germanic peoples are fairly rules driven ). This was a third party paid access lounge, which is clearly dependent on knowing who is going to pay for access.
That was last year (VA paid economy on Qatar).
Interesting to note that last week (QF award Economy on Qatar) the boarding pass included a note about the lounge to use. A middle eastern port without Qatar lounge, so in a third party lounge.