This is getting technical !!! As I said before, I am not currently employing totally procedural separation. However, are there not other factors which could apply?
1. If, after the fix xyz (I'll assume a VOR), the aircraft tracks diverge by 45 degrees or more, those aircraft will remain separated.
2. If the second aircraft has been instructed to hold at xyz, then the ten minutes will not be infringed.
3. Otherwise, if the two aircraft will continue on the same route, I still believe that procedural separation exists up until the instant that the second aircraft reports at xyz. By then, of course, it is too late to do anything and a loss of separation is inevitable. But, if the second aircraft had been cleared to achieve vertical separation by xyz, then we're safe.
Right, I hope I've dredged that accurately from the depths of my memory. If I got it wrong, rest assured that I will not be putting anybody's life "on the line" in this way. In fact, SRG WILL NOT PERMIT anything but the simplest (ten minutes, same speed) procedural separation to be employed at LATCC in the event of a radar failure. Their view is that, as it's not a skill regularly practiced, it should either be a part of the annual ECT refresher process or not permissable.