It is worth keeping an eye on them.
I'd make regular journeys to their webpages.
They have had financial troubles and operating difficulties in the last couple of years.
I'm surprised by what it says in their FAQs quoted above. That information is quite old. We haven't had bubbles (isolated family groups who only associate with each other to prevent the spread of covid and to prevent the bubble catching it) since before Christmas 2020.
I am as covid conscious as anybody, and more than most, but I wouldn't expect to travel in a bubble any more. We always mask and sanitise but virtually nobody else does. I have noticed an uptick in the numbers masking in the last couple of weeks now that the flu is so prevalent and the new variant of covid is out there, but most still don't.
I expect that the company is trying to cover themselves in case of strikes or company financial issues, and if they will be allowed to operate.
But that's a hypothesis - I don't know.
The issue you mention about Royal Mail and strikes is a very real one. Royal Mail was on strike for nearly 20 days in December, packages and post were delayed recently up to six weeks on important packages. 24 and 48 hour services have been taken away by companies and given to private contractors for critical packages because they simply weren't reaching the customer. At the moment they are not on strike but their issues have not been resolved and there has not been a settlement. They can call additional strikes with 14 days notice and more are expected. I personally am waiting for a card that was posted to me in November.
Half a million workers walked off the job on the first of February, across many many companies and government. More are expected to strike on the 6th.