One hour provides for a safe and relaxed transfer even if KA departs from a bus gate (or KA island). Your bags willl probably make it faster than you.
Even in 45min you would easily make it.
BA27 is quite punctual, very rare to see a delay of more than 30 min.
And if things go to worse, you still have the last KA flight 2+ hours later.
I don't see any sense of moving to the early 777 with lesser F seats.