I wouldn't say it's with delight, it's more a realisation that things changed with the rise in use of Low Cost airlines.
https://en.wikipedia.org/wiki/Glasgow_Airport#Annual_traffic_data
https://en.wikipedia.org/wiki/Glasgow_Prestwick_Airport#Statistics
https://en.wikipedia.org/wiki/Edinburgh_Airport#Statistics
https://en.wikipedia.org/wiki/Bristol_Airport#Passengers_and_movements
While Glasgow isn't meteoric in it's rise, and Prestwick has fallen, Edinburgh, and Bristol, two of the main markets for NightStar are unprecedented in their rises.
When LCCs started up, offering fares from less than £30 to Amsterdam and Paris NightStar was dead.
Even the relatively easy sleeper operations in Mainland Europe are disappearing.
While it would be absolutely fantastic of going to bed in the UK, and waking up in for instance, Amsterdam, the costs would be phenomenal.
It's true that low cost airlines are a part of the picture that wasn't there 25 years ago. And I'm very aware of the drastic cuts to continental services.
But the decline of night services on the continent is due to other and more complicated issues as well. Increase of high speed daytime alternatives on certain routes, and the changes to financing/operating that have come out of EU-led restructuring.
I think the jury is still out on whether night services are dead. The Thello operation to Venice still runs, under an open access arrangement, across multiple borders. I think we'll have to wait a few years to understand the long term consequences of the EU rail shake-up.
The choice between flying/sleeper train isn't a straightforward one based only on price and travel time (this discussion has been done to death on the CS thread).
Many of the arguments made for subsidising sleepers between London and Scotland could also be made for trains between Scotland (or the N of England) and, say, Brussels or Paris.
Of course there's the question of whether running through the tunnel would make it massively more expensive/complex than other cross border services. We know that passenger trains can run through because it happens every day and we know that there's no fundamental issue with loco hauled night stock because that's what the Nightstars were. This is why I wondered about the mk 5s. *If* (and of course only if) they could run through the tunnel without major alterations (or if a tunnel-compliant variant could be built to a very similar design), then in a few years we'd have a regular sleeper operation using locos that we know can go through the tunnel. So, compared to today (with aging rolling stock and until recently haulage that would be no good for the tunnel) the obstacles to contemplating services through the tunnel would seem considerably less.
I don't really expect it to happen. I'm probably too optimistic about the prospects for night travel. But what if it turns out that they've really nailed it with the new stock and the services become really popular? If it turns out there's a substantial market of people willing to pay a bit extra for a bit more comfort? What if something external changes, like fuel prices, that means "low cost" air travel becomes a thing of the past? Who knows.