Here seems to be a good place to post my Eurostar cancellation / rebooking experience.

I got an email on Thursday about the Brussels - St Pancras leg of Amsterdam to St Pancras trip being cancelled on the 1st September.

Whilst annoyed (I’d only booked it a couple of weeks ago) the email was clear to read and explained that It was the Brussels leg that had been cancelled (Unlike some airline emails where it was harder to work out hat had happened on multi leg trips)

The rebooking process was easy and it clearly presented me with a list of my options* for trains returning on the same day and was rebooked within seconds of hitting the button and them immediately able to select seats.

Switching to future dates there was no extra to pay even though the new booking fares had increased.

* and this was a full list of all available trains - I used another browser to check what was being sold - unlike BA which gave me a choice of 5 flights to rebook onto when there are at least a dozen on sale ...

Actually quite impressed especially compared to some of the airlines communications and rebooking processes.