It was a fairly low key announcement of the BHX base, at least it wasn't that prominently covered in national media (a cynic might say, well it wasn't in London!). Presently the public are all consumed in that annual jamboree and spending spree that is Christmas, and add in the ongoing covid-19 situation they perhaps felt that their route announcement and opening of reservations might have been lost in the fog of health concerns and retail therapy.
Post New Year, when, covid permitting, there might be less going in the public consciousness and announcement of a regional airline opening new routes will cut through better. I'm sure they know exactly which routes they plan to operate and the start date but clearly unlike inside the walls of Downing Street, their premises are pretty leak proof.