Reporting live from the 18.03 with difficulty thanks to the ride quality, and using 4G as I've no idea how to make the onboard wifi work; the 17.48 only ran as 5 cars, not 10 and this one is definitely full. And there seem to be no seat reservations on LNER services at the moment.
So I would say: yes, actually, people are travelling again, with and without masks so they are busy that some might think. To be contrary I'd have pulled the Peterborough stop on this service if it's only going to 5 cars from now on. The more Mk4s we get back into healthly service, the better from where I sit (D19).