As is widely covered in the '
Transit Without Visa' thread, it's acceptable to book travel of the form LHR-PVG
(144hrs)-HKG
(1hr)-LHR (or swapping around HKG/PVG) to visit Shanghai under the Visa Free rules. (Essentially, booking a ticket with the outbound or return routed via HKG, as BA is apt to offer anyway).
Although I'm clear this is acceptable with the Chinese authorities, would this be likely to raise any eyebrows at the Visa Check desk at T5, or are they used to it? Just wondering how much extra time to allow concerning BA in particular, etc.
Thanks!