Quite a few of us in the thread have been stung now it seems, a lot of posters mentioning Germany too.
There is another thread here now called "Postage prices to Europe sky rocketed?" (posted by Craterloads) and it seems to be a similar issue but other other way round. Seems like on that thread that it's a supply vs demand issue.
The price hikes are because no couriers are taking parcels that will be delivered by road - they have a backlog to get through the port as it is.
They're only quoting for air freight which is a lot more expensive.
As for the rest of the thread, 99% is down to the France - UK border issue due to new strain; the capacity of this link for parcels was always quite stretched and the backlog from the short closure has meant a lot is still held in warehouses until there's capacity to clear them.
I've had an absolute nightmare with this at work; air freight was never affected (spare capacity down a little due to less passenger flights and some of the 'held' parcels mentioned above being replaced by air freight) but anything by road sent since mid-December has been glacial.