Your Colt is absolutely correct historically. No way it's value would be affected. And considering what's been happening to handguns in England, it's value will surely increase.

In the USA we have so many more of pre-WW2 guns readily available that I think we are a bit spoiled.

I do remember a number of years ago that many collectors turned their noses down at British Import/Export markings...

I don't like import markings and as said before by others, it knocks it down to almost shooter price - however, I would not turn down a rare model with one. A friend of mine had a 1925 Simson - I would gladly buy it if I found it for sale.

I certainly don't consider myself a serious collector, let alone any kind of an expert, but for me an import mark automatically puts it in the shooter category just as if it was nickle plated.

I hate marks in general but I think we should consider the fact that "import marks" and "proof marks" are two different things with different meanings.