If booking close to the time you may need to include an overnight stop in Brussels and take the 06:25 ICE to find a London-Spezial, or at least a reasonably priced one. Sometimes you will need to put in a 2 hour stop-over in Brussels to find London-Spezial fares if the Eurostar and ICE do not connect. I'll also repeat a piece of information I often give: if there are 59 € fares to Aachen/Köln, then they are available to anywhere in Germany, as soon as this becomes 69 €, it could be 169 € to somewhere the other side of the country, and the price depends on the quotas for trains within Germany, not just the Brussels-Aachen/Köln quota.