Once the general price level has gone above a certain level (i.e. the price bucket in which pass holder seats are is full), there are no pass holder seats available anymore. There's not a fixed number of pass holder seats. That also means that a lot of cancellations (of any ticket type) would be needed for pass holder seats to become available again, especially during busy times, such as the end of December.

That being said, in the past summer, Eurostar did sometimes open, often a few days in advance, some extra seats for pass holders, despite the price level already being very high. But nobody knows whether they'll do that again.

If they add extra trains to the schedule then the initial fares available will be below the highest band for passholder reservations and these will be bookable.

In general this only happens if they have not fully released the full timetable initially for some reason, sadly they don’t routinely add in extra trains just because the demand is high.

Thank you @rvdborgt & @Al_G. It appears changing hotel reservations is going to be the best route. Thanks again.

Before Covid and Brexit you had more Eurostar services than today... We’re still having less trains than in 2019 e.g., while travel seems to be almost back at normal pre covid levels.

Nobody is quite happy with the current situation. Even Eurostar. Apparently Brexit limits capacity in the London terminal with 25%.

Nothing left but to hope that they will add in extra trains soon, we’ll see.

I hoping they do as well. Most of the trains for the 30th are already sold out.

That then also means that many people have snapped the 1st cl seats-whereas normal bisnistravel in that week is minimal to nil.

2nd class London-Paris is fully booked on 30 December, so people who absolutely want to travel will book 1st class. Trains between 8:00 and 15:00 are fully booked, also in 1st class.

 After the recent spate of posts on the lack of seats on Eurostar in the run up to Xmas I have been checking E* own site for pre Xmas. I was a little surprised to see that the price difference between Standard and Standard Premier (pass equiv 2nd/1st class)  is relatively small on some trains.

However they are though  still expensive for a 2 hour journey (£100 - £200+). I would alsoeither have to add the cost of Leeds to London or use a travel day to get to St Pancras.

I can get a flight from Paris to Leeds or Leeds to Paris at pretty much the same price and it would only take about 3 hours from my front door to Paris CDG.