Originally Posted by
andyr
Actually, I believe the "standard rate" is the 40 GBP rate (i.e. premium cabin). The "reduced rate" is the 20 GBP rate (economy cabin). So, you have to read "standard" rate as "premium / luxury" rate.
The cases outlined in the regulations cover domestic connections ("domestic" in the UK sense, i.e. UK-UK-UK) and international connections (i.e. UK-UK-somewhere intl, or UK-intl-intl). There is an example for LHR-MAD-RIO that states, provided that the 2nd flight is within 24 hrs of the 1st flight, if a higher class of travel is used for either LHR-MAD or MAD-RIO, the standard 40 GBP APD is due (vs. the reduced 20 GBP APD). This would seem to be directly on point to the example cited by the OP, and (regretfully) the flight number doesn't matter at all.
http://customs.hmrc.gov.uk/channelsP...0505#P128_5937
There is also some discussion of situations like AA's MAN flights with a F cabin sold as Y. If the selection criteria for booking it isn't "first come first served", additional duty is supposed to be paid.
None of this is sensible, or good news, but those do appear to be the rules.
I think you have the answer there (although note that the £40 rate was doubled to £80 in February). As you say, it makes no sense but AA seem to agree and are convinced that it's payable in these circumstances.
Originally Posted by
TerryK
Sticker upgrades are different as tickets are not reissued for upgrades. You are simply rebooked into a higher class of service with stickers. Your eticket still shows the original class booked. For mileage and eVIP upgrades, tickets need to be reissued to reflect the higher class of service, hence the APD collection issue.

It does look like the key issue (at least from AA's viewpoint) is the issuing of a new ticket reflecting travel in the premium cabin on the connection. That would explain why others, including me, have never been asked for the higher rate when they've been upgraded on the domestic leg by stickers or through complimentary EXP upgrade.
I've been back to AA and received the same answer twice. However they confirm that, should I be upgraded automatically in the upgrade window or at the airport, I wouldn't be asked for more APD. They've been helpful enough to split the flight into 2 segments.
Reluctantly, I'm going to leave it at that and hope for the upgrade clearing anyway. Not happy but resigned to failure on this one.
Thanks for everybody's input on this.