Booking flights to Belfast for the family I came across an anomaly I’d not seen before when doing two single bookings rather than a return (the reasons for doing singles rather than a return I won’t go into, but it involved me getting an Op-up last week when I was on a different PNR to the rest of the family, and ending up in CE, but also the dog house....)

Taking the lowest return pricing it is £61 each way, and shown as such when you select your flights (with the booking screen showing fare of £10.00, taxes etc. of £110.80 and therefore a total of £120.80.

However, book it as two singles and it is no longer £61 each way, but:
LHR – BHD £84.30
BHD – LHR £36.50
It adds up to exactly the same, but to show it when booking a return as costing the same each way is a bit disingenuous. I almost booked us all on EZY to get there (Mrs LA wants to fly from LGW anyway) but decided to use Avios for the outbound flight instead and pay cash for the return – ends up being a value of 1.6p per Avios which isn’t the best value but still OK by me compared to 1p per Avios if you book using Avios both ways.

Of course it comes down to taxes
Air Passenger Duty - United Kingdom £13 each way
Passenger Service Charge – United Kingdom £19.50 LHR to BHD only
Another Passenger Service Charge - United Kingdom £28.30 LHR to BHD only
European fuel surcharge**/US carrier charge*** £18.50 each way

I wonder if there is any reason that they split the total price in two if buying a return, but not when buying singles. If I was flying this route frequently I'm sure I'd fly EZY one way and BA the other!