I went through yesterday arriving t3 at 6:30 am and did the domestic connection route at t5. Looked busy, honestly, didnt take that long even with long queues and the bus from t3. I hate t5, but i grudgingly admit it doesnt take that long. They have the new system at security (4 spaces for trays, but i did have to point people in front of me to a space as the security staff as ever couldnt be bothered) and everything for once seemed fully staffed, even at the domestic connections border point where i have often seen only one or two staff - there were four, maybe even five (if space) on for dom connections. Anyway, i had a 1hr 40 connection time and had 30 mins in lounge, even with the long walk at t3 and the bus to t5. For you i'd more watch if ba207 is on time, never was when i used to take it!

As for your man flight you wont even know the gate until about 40 mins prior and wont board until 25 mins prior to departure at the most. Also man flights typically leave from the low numbered north gates (sometimes south but usually north i believe).