Originally Posted by toryvict
hi, i'm planning a DONE4 myself, so i feel your pain.
you're limited to 2 LHR-middle east segments.
So your LHR-DXB-LHR-IST-LHR is 4 segments right there. You may need to use HEL or MAD as an alternative.
Good news: IST is -not- in the restricted list, so LHR-DXB-LHR-IST-LHR is perfectly ok.