In the U.S., lower 48, I know of no airport which regulates how many engines one must taxi with. I fly the 319/320, inbound taxi I can cross a runway virtually as fast SE and with two. Outbound taxi depends on weight, contamination or local requirements (tight turn from gate)
I flew into LHR regularly years ago and don't remember that restriction, although we didn't taxi SE in the -777 and -767 so it would not have mattered.