Hi Alex, it may be of interest that the Swiss Rail site, sbb.ch as mentioned by you, not only gives times, but fares as well, including Thalys and Eurostar. I checked the fare from Munich to St. Pancras in 1st with a special offer of CHF 380 (many fare options are shown) which is about €315 so just slightly more than the Munich – Brussels fare alone paid by JohnHarper.
Not only can you book online, but you can also choose seats and have the ticket sent by post or DHL to your home. In some cases you can even have the ticket sent to your mobile phone. Of course the post option would not have been possible for John but it would have given him an idea of price. The local station could issue the ticket.
It’s also worth noting the Rail Plus card which gives a 25% discount on rail travel throughout Europe as long as a border is crossed. The Swiss Half Fare pass gives 50% off Swiss rail travel and 25% on German rail tickets if starting in Switzerland. All this can be bought online and sent.
For European train travel I think this is one of the best sites going and I use it regularly.
Edited to add: The Swiss Half Fare card gives 25% off all tickets in Germany and Austria without the need to start the journey in Switzerland or cross the border. Frankfurt – Munich or Munich – Salzburg would both have the discount for example.