Comms bod employed by football authority left after large blunder (8)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Someone employed by the Football Authority to handle public relations (comms) might be known as PR AT FA ; then L (abbreviation for left) after L (abbreviation for large). Pratfall = originally a fall landing on one’s buttocks, but now also used to mean an embarrassing mistake.