As a hypothetical trip, I would like to do:
Perth (PER) - Abu Dhabi (AUH) - London (LHR)
Dublin (DUB) - Abu Dhabi (AUH) - Perth (PER)
Flying First Apartment for the AUH - LHR leg only, redeeming through Velocity points.
In order to do this, would you need to book the economy and 1st Class flights separately, or could you book it all as economy and upgrade the LHR leg? Would it be much better to make it a return to/from LHR, rather than departing from a different country?
By booking separately, you pay 78k for AUH-LHR in First Class, 42k for PER-AUH in Economy. You pay 177k if you redeem it as 1 single redemption. So in this case, there is a saving in point costs to book separately. However, it comes with its own pros and cons. Pros include a free stop over in Abu Dhabi. Cons is if you have a short connection time in AUH and you miss the 2nd flight due to a delay on the first flight, because it is 2 separate flights, the airline isn’t liable and you will no show your 2nd flight. Whereas is it is all booked on 1 ticket, you will be covered for the 2nd flight if your 1st flight causes you to miss your 2nd flight.
Try and avoid departing from the UK to avoid the APD tax. However, this may be only valid when travelling in premium cabin.