Hi,
First of all, welcome to FlyerTalk and the BA forum.

As you are on one ticket, you will be protected in case of delay to your inbound flight. Normally, you will be switched to the next available flight at no charge. There is a later BA flight to HKG which I would expect them to put you on provided there is space.

If your inbound flight is on time, 60 minutes is normally more than enough. Given the short connection, there will probably also be a BA agent waiting as you disembark the aircraft holding a sign with your flight number. They will help you make your connection.

As soon as you clear security, check the departure boards to see which part of the terminal you leave from. As you say, the B and C satellites are a short train ride away but the route to this is well signposted. Any member of staff will also be able to point you in the right direction.

Safe travels.