No, they were all scrapped in 2020 when people were banned from breathing outside and the companies decided to use passenger ferries to run freight, choosing to cash in on scrap prices rather than laying them up. Because obviously the world was going to end.
Take half the Dover fleet out of service and suddenly you have a backlog. Hardly a surprise.
Stena have shuffled their fleet in response on certain routes by postponing annual maintenance. But that doesn't help Dover any because they haven't operated a service from there for years, Dover Calais effectively being a P&O monopoly.
That said, Folkestone and Ramsgate haven't had a meaningful ferry service between them since I left school.
There is always someone else to blame first it was LeShuttle, then the end of duty free, then Easyjet, then Batflu and Brexit, but there's as much freight going through Dover now as there was before the referendum, but at no point did anyone stop and say 'hang on a minute, we need to ramp up capacity' the same short-sightedness that built two single track tunnels under the sea to run constantly conflicting services. Best thing to do with it would be to stop the passenger services and turn it into a continuous loop, like a baggage conveyer. It might take longer to do the crossing, but being a continuous loop, there would be no delays and no wasted space. You simply join the queue at one end, and literally non stop, drive off the other end.
Operation stack has been a 'thing' for decades, so that's not a new problem either.
Basically the system has zero contingency capability built into it. And effectively shutting down P&O with red tape BS because they changed employment agencies is a self fulfilling prophecy.
Just enough capacity is never enough. And it's about time that those responsible accept that they either need to invest in more infrastructure or stop importing everything*.
*Obviously that's no longer an option which leaves more infrastructure.