An hour later, the reality became clear, as those taking part in the discussion, hosted by think-tank Planning Futures, strained to hear each other over a rousing chorus of Rule Britannia from a nearby room, into which most of the activists had filed. The planning event, it transpired, was being held at the same time as a Democratic Unionist Party reception attended by DUP leader Arlene Foster and Brexit secretary David Davis.
Next up, further evidence that the planning profession boasts some of the nation's finest minds. Joe Sarling, associate director at planning consultancy Lichfields, has been named "geek of the week" by ITV politics show Peston on Sunday.
Sarling, whose graph on the topic of house price to earnings ratios since the 1950s was displayed on the show, said: "It's fantastic to have research understood and shared on a mainstream poltical programme." His colleagues were less impressed. "He'll be insufferable tomorrow," tweeted Lichfields senior director Matthew Spry.
Finally, news that actor Michael Sheen has lent his support to opponents of a waste plant in the South Wales Valleys.
The Newport-born actor sent a letter of objection to a public inquiry into Hazren Environmental's proposals for a waste treatment facility at Nine Mile Point Industrial Estate in Cwmfelinfach, near Caerphilly.
Sheen claimed that the need for jobs and industry in one of the most deprived areas of Wales should not "blind us to the risks to the health and wellbeing of communities".