Does anyone know any mechanism whatsoever by which a xONEx ticket can be linked to another air ticket, with the goal of getting the onerous UK APD (Air Passenger Duty) waived/refunded?

For example, we're currently scheduled to travel GRU - LHR on BA as part of a DONE5, and wish to purchase an additional international ticket ex-LHR for the same day as the arrival, and wonder whether there is any mechanism whereby the 2nd ticket can be sold without the APD (GBP 90 per passenger). I spoke with BA reservations in London and they asserted complete ignorance about any possible mechanism, despite both flights being revenue tickets on BA.

Given all the Herculean efforts that individuals and corporations exert to avoid taxes generally, and as the UK APD rises into the stratosphere, it seems unfathomable to me that there would be no mechanism at all that transfer passengers can request to avoid taxes that were not intended to be applied to them. Is there in fact a mechanism to achieve this goal?

Thanks in advance!