Dan Cole created a maul, so Woodcock was offside.
Yeah, all it needs is one person to engage and then it doesn't matter if he disengages. The fact that this lineout tactic exists (albeit not successfully done here) is also why people were so amazed at Dylan Hartley not knowing about the ruck version of it.
Cheers guys. The bit i have bolded is what i wasn't so certain on, so thanks for clearing that up.