The "Star Alliance" office (effectively LH/OS/AC/UA) on 7-8 Conduit St was very useful too. The 2 ladies who worked at the LH counters were absolute gems. One of them spent an entire morning patiently re-booking a messed up RTW for me.
I was told that the office closed because UA did not want renew its share of the lease. IIRC QR took over the premises.
P.S.: Isn't the Biman Bangladesh Airlines office somewhere nearby too....?