Hi Guys,

I've been planning a trip to the US next year and looking at different options in terms of dates and locations. I've asked a few questions on here which have been answered promptly and you lot have been a great help. I've got another minor question, but first to summarise what I've learned so far and a summary of my learnings...

- I'm looking to fly from GIB via London using Avios. I can't book a reward flight on that route online so I'm going to need to call to make a booking.
- I can use a BA Amex companion voucher and a Barclays Avios Plus cabin upgrade. I'll be booking myself and my son in Business using the companion voucher and paying a Premium Economy amount of Avios for my wife in Business.
- Reward flights sell out quickly, as I type there are only a few dates available at the end of July and beginning of August. We're looking to fly end of Aug so I'll need to call as soon as possible when flights are released.

My question this time is related to that last point and the impact of tax.

I understand that as I am flying from Gibraltar I will be paying reduced tax as opposed to flying from London. If I split my booking into two (e.g. calling to book the outbound leg first, then calling to book the return when that is released) how does that affect my tax? Would the tax on the return leg be calculated differently if booked as a round trip to and from Gibraltar, or is it the same as if I booked a single-leg journey from the US?

I hope that makes sense. Thanks again to all the great people who post here.

Mark