Catalancs answer is better than the real one - which is that it was played on a Wednesday afternoon to conserve electricity due to the miners strike.

Don't think that the Captain Morgan Trophy was the same as the ITV Floodlight Trophy. I remember Bradford Northern playing in the Captain Morgan's and they had no floodlights at the time (round about 1973). Think the ITV Floodlight Trophy was a one off thing well before that.

Correct in that it was Wire.
Warrington are the only team to have won the ITV Floodlight trophy in 1955/56 season, this is the only time the trophy was played.