Now he has made the short trip down the A180 to join United's fiercest rivals - signing a one-year deal at Blundell Park.
"Peter has proven quality and is a great professional," said Cods boss Graham Rodger.
"Not only will he give us excellent quality from set-plays, he will also give us quality in wider areas.
"He's not just a provider though, he is also a good all round player as well.
"I've seen him play a lot over the past couple of seasons and he still has a lot to offer."
He will make his debut for the Cods in a pre-season friendly against Gainsborough Trinity on Friday.