LHR Minimum Connection Times

I can't see this topic elsewhere on the search so...
I wish to fly to JNB in September from Aberdeen after my sister's wedding. The ABZ flight arrives at terminal 1 at 1915 and the JNB departs terminal 3 at 2100. Will this be plenty of time to make the connection? I know this service hasn't started yet but wondered if anyone had similar experience connecting with BA or bmi at the same terminals. IATA quote 75mins minimum connection time but the BA flights on this route are often delayed 1hr or so which is why I am concerned.
The flight before this one arrives at 1335 resulting in a long wait at LHR. Unfortunately I will only be in PE so won't have use of the clubhouse - just 3 hours at the the No1 Traveller Lounge
Also, does anyone know if we will be able to book multi-city trips online (or have I missed it on the website?) I wish to book a flight from LHR-ABZ before the wedding and return from JNB-LHR at the end of my holiday. Currently I think the only way to do this is over the phone.
Many thanks,
Steven
I wish to fly to JNB in September from Aberdeen after my sister's wedding. The ABZ flight arrives at terminal 1 at 1915 and the JNB departs terminal 3 at 2100. Will this be plenty of time to make the connection? I know this service hasn't started yet but wondered if anyone had similar experience connecting with BA or bmi at the same terminals. IATA quote 75mins minimum connection time but the BA flights on this route are often delayed 1hr or so which is why I am concerned.
The flight before this one arrives at 1335 resulting in a long wait at LHR. Unfortunately I will only be in PE so won't have use of the clubhouse - just 3 hours at the the No1 Traveller Lounge

Also, does anyone know if we will be able to book multi-city trips online (or have I missed it on the website?) I wish to book a flight from LHR-ABZ before the wedding and return from JNB-LHR at the end of my holiday. Currently I think the only way to do this is over the phone.
Many thanks,
Steven
