I feel that some people have misinterprated one four sick's original post.
The Brit A/C was not being asked to slow because of the Iberia ( and preferances for same nationality carriers, although I'm not saying that doesn't happen) but because of the backlog of aircaft caused by the published approach speeds.
This seems to me, a rather strange thing to get frustrated by. Surely airmanship and situational awareness would have made him understand why the preceding two aircraft were slowing.
Unfortunately it does open the door for generalisation but I don't believe this indicative of Brit pilots, the ones I know at least. Who are all very professional, courteous people, who aren't quite as impatient as their colleague.
Regards
le loup garou