Maybe COP's problem was that the WPL deal was the only one on...

Maybe COP's problem was that the WPL deal was the only one on the table at the time and they were forced to dance to WPL's tune, this then set the bench mark at a time of extreme uncertainty in the market.
COP knew the deal would attract others, they even covered their bets telling WPL they would be reimbursed if it fell through and at the same time acknowledging that it was subject to PE and government approval.
As predicted once the ice was broken others wanted in for a swim, especially as the sun came out and the water became more inviting.
Very smart move by COP with no downside and there was just the possibility it would slip through especially if it was wrapped up in grease proof paper.
All conjecture on my part but you know what they say !

"You have to bait up with a sprat to catch a mackerel"