A repost of an earlier posting by me:-
I used the link service between Edinburgh and Waterloo back in 1995 (or it could have been 1994).
It was a bit of a faff. We booked the hotel and Eurostar through a travel agent, but the connection ticket had to be bought at Waverley using evidence of the Eurostar Journey. Sounds simple, but the Eurostar ticket was to be collected at Waterloo... Then there was the hassle of wanting to spend two nights in London on the return trip...
I'm sure the service was quite early leaving Edinburgh, there are distant memories of being in Waverley about 7am, which meant getting early connections to Edinburgh.
The service itself... Erm, well my brother and I were the only 2 passengers on the HST as it left Edinburgh. The buffet manager walked through to our coach to take our orders for any refreshments - and invited us to move through to 1st class so he wouldn't have to walk so far to bring us the snacks!
A few passengers boarded at various stops in England, with lots of confused faces of passengers on the platforms as warnings were given that the service was for international passengers only. We were the only ones that were upgraded - so had 1st to ourselves throughout. When we reached Waterloo I counted fewer than 40 passengers disembarking.
The route arond London was a strange one, we seemed to skirt round various places using what looked like freight routes - sometimes at walking pace. I do recall seeing the TVAM building at Camden Lock.
Passenger loadings were similar on the return trip, there were was just the two of us disembarking in Edinburgh on the return.