With BA upgrading DEN to a 4 class 744 service and LH dropping First Class for the summer, BA now becomes an option to/from internationally challenged DEN.
So Mrs. SFO777 and I are throwing caution to the wind and giving BA another go next week.

A few questions since I haven't connected at T5 in a long time.

We're flying LIN-LHR-DEN with an 85 minute connection. Is LIN-LHR likely to arrive at an A Gate? A real gate or bus gate? Do we re-clear security at LHR? If the inbound is reasonably on time, can I assume that we have plenty of time to make our connection?

Re seat selection on LHR-DEN, my AA confirmation shows 1AK. But BA.com and my BA app both say "Seat choice available" or "--" as in no seats assigned. But when I click on "Choose your seats" and "Reserve Seats", the seat map pops up and shows us in 1AK. The seat map on EF shows 1AK blocked instead of occupied. What are the odds that we really are in 1AK? FWIW, I'm OW Emerald, but Mrs. SFO has no OW status.