Thanks for the info.
I am on a 2 for 1 voucher, so cannot use IB (as far as I know).
I think I may take the short connection on outbound and if missed, just stick around for the later flight (5 hr. layover at the Club). Then stay at a MAD airport hotel that night before heading on south of Spain vacation.
On return, probably fly in the afternoon before, get a hotel at LHR, and then catch the LHR-PHX flight next day.
Sound reasonable?