Eligble for 72 hour Transit Visa

Yes, you can avail this 72 hr free transit in Beijing if you have confirmed ticket leaving from Beijing to Hong Kong.

I have a similar itinerary, just wonder if someone can clarify:
1) Does the same apply if this is a straight transit, ie arrive Beijing from London, then depart to Hong Kong on the next flight (through-ticket)?
2) Do you pass through China Immigration for Entry and Exit, and if so, what documentation do you show them to pass through?
3) Is it exactly the same if flying Hong Kong - Beijing - London on a through-ticket?

I think you might confirm this with Beijing Airport Immigration Inspection at 0086-10-56095400.