I am going on a limb with the above frame. Dad made a few bikes for a Canadian Maurice Johnson. My gut says, since the bottom bracket number is NOT part of Dad's book. This is a frame NOT made by Colin Laing. Maurice could have wanted a repaint back in those days and said just put your stickers on it. Thus why you are also seeing a chrome Masi fork.
Dad would not have put that type of cable guide on the bottom bracket.
cheers
Stuart