Thanks. Sort of my feeling. Really don't want to go with the 4:45 connection. I mean the lounges at MAD are nice...but not that nice.
OTOH, this is the last flight of the day to GRX for the day, and the next is 11:50 the following day,
I know that LHR will often do an expedited transfer in cases of tight flights like this with an agent escorting folks. Not sure if MAD might do this in a case like this.
Also, not sure if BA (as marketing carrier) are on the hook for accommodations if this is missed since they have booked this as a connecting flight (the IB site lists it as a legal connection as well), or if it's on us.
Cheers.
There is a tight connection queue for passport control and I'd say if you're toward the front of the plane it should be doable. But as you said the risk of a delay making it the last flight of the day is pretty high. Note that the GRX flights leave from the far north end of T4 main so that's another 7 or 8 minute walk once you're there. (still think it's doable for a reasonable mobile person)