I believe that Eurostar drivers do not have much route knowledge in depth as a mainline driver does. But need to know multiple rule books.
As the computer highlights the speed he/she should go at all times.
You may well be right whilst on a cab signaled line, Ashford being a colour light signaled line our route knowledge is exactly the same as any other driver. In this case the problem at Ashford concerns the separation between 25kv AC areas and 750v DC areas, the resulting potential differences short circuit through a electronics card on the E320 - this 'fried' card is used for SNCF classic line signalling. The consequence of this unexpected problem is that E320's are not being diagrammed to call at Ashford - with stops being cancelled accordingly. In an emergency the units can still stop.