But are those going to London? They are in London, as are some other loop services e.g. Hounslow. Arguably any route with both ends in London would count! Unless being the same route both ways doesn't count in the first place.
I can, and do, go to London both ways from Wokingham. True, going via Reading involves a change, but is usually quicker. Does that not count? Or what about 17th February, when I can get RRBs▸ both ways to get to London ...
Wonderful questions, to which there are no definitive answers.
We are physically a long way from Sheffield ... looking at a wider passenger experience (and thinking "Wokingham" too), I find myself asking "what's the best way from A to B for me?" and the complex information systems and choices involved - not only in timetabling but also in knowing the best way to make the journey when services are not running to timetable, and in ticketing, price of journey, etc.
Localising, as I tend to - the multi-route journey I make from time to time ... Melksham to Bristol ... lots of options there but what a mess working out the "best" and especially on the return, see the look of panic in the customer service advisor on the gate line when you ask what's the best way (now) to get back to Melksham. The question is a reasonable one that the person does not have the tools to practically answer ...