So- how does this work? I have always booked dates out when it becomes available and then added the return when that become available. But today after 2 hours and 2 minutes on the phone I am no further forward.

I booked an out avios in 1st from LHR to USA. I couldn't book a regional connection as there isn't one on the same day and it wouldn't give me an option to book a stopover. Not a problem- booked the same flight last year and had the same issue.

Today the return became available and so I tried to book the return and regional legs. I was told that adding a 2nd leg to an avios had a £35 each charge anyway.They said I had to pay a change fee to add a 2nd leg- argued that and got it removed.

They then said that I could have booked a regional - USA when I booked the first leg and so have to pay a service fee of £35 each (I couldn't I tried).

I was told that I had to pay additional avios for the regional legs? That was eventually sorted.

The issue that remains is that I have to pay 2 X1 way taxes which is £749 -is that right?

I paid £449 for 1 was LHR to USA out. Today they tell me that a single return from USA is £591 but I only have to pay £300ish. This is only LHR- USA- the regional hasn't been calculate yet.

To book the same flight today as a return is £600.06.

How is it calculated?