There's no such thing as a MkII Bailey bridge. There's BB (Bailey Bridge), IWBB (Improvised Widened Bailey Bridge), SWBB (Standard Widened Bailey Bridge)and EWBB (Extra Wide Bailey Bridge). There's BPB (Bailey Pontoon Bridge), BSB (Bailey Suspension Bridge), and even BDB (Bailey Deck Bridge) and BLB (Bailey Lock Bridge) but nothing called a MkII Bailey Bridge. In US parlance the various widened Bailey's were given an M classification.