I am planning on the following DONE4

SYD-HKGx-LHRxEDI-LHRx-LIN-LHR-DXB-LHRx-CDG-LHR-LAXx-MIAx-BOS-ORDx-LGA//JFK-HKG-SIN-HKG-NRT-HKG-AKL-MEL-PER-SYD
(x denotes transit stops - less than 24 hrs, // denotes open jaw)

Just want to know for the EDI-LHR and CDG-LHR (Return) I am planning to purchase a seperate BA Ticket for them. Do I still need to pay th EXTRA LHR landing fees if it is not part of the DONE4? Therefore 5 sets of LHR fees compare to 2 sets.

Also if someone wouldn't mind can they work out the tax of the above for me!! (as I find my agent ALWAYS stuff up the calculation on DONE4!)

BTW, how much are the LHR landing fees and tax??


Thanks