Am I missing something here? Your supplier was arriving just after 11pm and your return flight was departing just after 1am. By the time your supplier got off their plane and passed through immigation and security and then walked to find you it would be, say 11.45pm. And boarding for your return flight would start at 12.15am. So you were intending to fly for over 12 hours just for a maximum 30 minutes meeting? If this is the case then it just seems weird.

As an aside I am surprised the HK supplier even agreed to the meeting in the first place, unless it is a very significant contract indeed.

Hong Kong has implemented a policy that all inbound passengers except from China, Macau, and Taiwan must do a mandatory 14 day quarantine in an hotel room (no home quarantines anymore) without being allowed out of said room. It is proving a successful disincentive to travel.

Maybe the supplier was planning to stay airside as well.

My heart really does sink when I read posts like this. Travelling 1/4 of the way around the world in the middle of a pandemic, in UK lockdown, for a few hours in Doha airport?
I know I’m on a frequent flyer site, but I am still shocked. Regardless of the value of the contract/what value the OP puts on the meeting, the world really does need better than this.

it’s interesting the strength of opinion: I would never countenance this unless a passenger had been violent/threats of violence etc. A complaint through the normal channels surely should never result in this. Even if wildly inappropriate (which this one isn’t...) a passenger should be declined, not banned.
And to the OP - there is no harm in making a complaint - you may find a sympathetic CS advisor who provides some relief beyond what they would normally do. I just wouldn’t expect anything.

I gather that was the idea: they'd have a confab airside, in the lounge.

JessicaB's point was that with all the faff surrounding arrivals, they'd likely have well under an hour together. And that short period vulnerable to collapse under delays.

Welcome to Flyertalk!

That's the point of doing the meeting airside in the transit area, there is no immigration, just security, you'll be in the lounge for the meeting within 20-30 minutes of landing at Qatar even with a bus transfer, so 23:30. For my 01:40 departure, I'd be leaving the lounge at 01:00 or so, so that's an hour and a half meeting.

I'm much more au fait with the setup in DOH and the logistics of holding airside meetings, but I've never been to the new IST.

Transit is allowed, the vast majority of pax passing through DOH are in transit.

What I meant is that you could have met in a nice hotel by the water the next morning for breakfast. Much nicer than airside at DOH in the middle of the night!

A visit to Turkey would mean self isolation for 14 days on return. If going to DOH and returning no self isolation is required.

Provided that your supplier's flight isn't late, that there aren't lines for security, that they are not stopped and manually checked. I would go as far as to say that by flying such a long way with all the current travel restrictions, having a brief meeting with someone airside and then flying straight back you could alert the suspicions of the authorities. As has been said already, this may seem normal behaviour on Flyertalk but to the outside world this would seem very strange given the pandemic.

If I may, I'll just reiterate my thought process on this, as there seems to be some hyperbole and misinterpretation.

Historically I have done many long haul round trips where I don't exit the airport secure area, in particular at KUL, HKG, BKK and DOH, certainly well over a dozen times in total, and it's never even crossed my mind that this was treated as anything other than a transit because no immigration formalities have been used.

I now understand that a back-to-back is technically not treated as "transit", so I've learned something new.

That last point is absolutely key: a number of posts have assumed that I knew that, which was not the case, and I still consider it be a reasonable assumption based on my own practical experiences. I now accept that my understanding, while empirically working well in the past, turned out to be technically incorrect. A case of mismatch between causation and correlation if you like.

For the avoidance of doubt, I was never disrespectful to anyone, far from it in fact: I found the the Qatar check in staff were particularly helpful even though after 90 minutes it didn't work out in my favour, as well as the BA representative at the airport who I requested to kindly log that I was at the airport and intended to fly (i.e., not simply a no show). Once back home, I did question how fairly the case was being treated when a BA representative made a series of incorrect assumptions over the phone regarding my travel, and which BA have subsequently accepted as such. I don't think it's the rep's fault, more to do with the corporate culture overlords nowadays who've make it so. Irrespective, it doesn't look like I'll be gaining much out BA anyway.

I hope that clears that up. We all make genuine mistakes, and I've now accepted it was my mistake. Hopefully I can gain some opportunity of redemption, although this has been a tough crowd.

How often have you transited DOH in F/J I wonder? That is as good a reason as any to conduct such meetings, transit is reasonably quick and smooth IME of dozens of transfers. Minimum connection time at DOH is 45 minutes by design.

I've done this dozens of times, just not in a pandemic.

It is.

You're very welcome to your opinion. :-)

If this was for the supply of safety of life equipment and infrastructure, would you have a different opinion?