Looks like the on-line tool has had the new rules implemented. I am able to price up the following itinerary:
Under the previous rules those four Europe-Middle East flights were not allowed.
Edited to add:
But if I change the last flight to be DOH-CPT, then the tool flags the LHR-DOH as invalid - saying:
2622: Your itinerary cannot include any flown or surface sector between Europe and the Middle East. Choose another route and update your itinerary.
Go figure
There is definitely no such wording in the new version of the rules, so I presume this is simply poor programming
Will continue to investigate...