Looks like you know most that there is to know about them. These aren't really Colt's version of the Victory, more the pre-Victory BSR, as they did not share the utility finish of the Commando, but had regular commercial finish and stocks. S&W produced the Victory version of the BSR, but Colt did not make a Commando version of the .38-200 revolvers.
The W stamp is the mark of Woolwich arsenal. There are some discussions, including in Pate, about connecting this stamp to the Dutch by way of their queen's name, but this has not been substantiated in any way and makes little sense given the time frame.
The VP, as you probably know, is the Colt "verified proof".
As for the numbers on the side of the frame, I have no first-hand knowledge, but a similar marking on another 38-200 OP, also a single digit over a 4-digit number, was explained as an Australian marking denoting the military district (top) and an inventory number.
Since we know that at least about 12,000 of these went to Australia, maybe more, that seems the best explanation.
PS: Just checked my old notes. The 3 supposedly denotes the 3rd Military District (Victoria). Again, no guarantees