I'd still like to know, though... will an ST here in the U.S. run software from England or Germany?
For the most part yes, software from the UK and Germany should run okay on a North American unit.
Occasionally there might be screen position or timing issues, but there is a 50/60Hz switcher program you can put in the AUTO folder that switches your ST to the European refresh rate. You can find the program in this older thread:
I am assuming you are using an RGB monitor with your 1040ST. Most composite monitors should also be okay with the timing changes. I am guessing you're not using an RF cable to a TV.
Of course if your game needs to auto-boot its own floppy, and won't start from the desktop, then you might not want to write any new files to the disk.
In addition to timing issues there are of course the usual TOS compatibility issues from time to time. But that applies to North American sourced software too.
Most of all of this has been addressed by developers over the years who have updated the older games to work across different TOS versions and automatically switch the refresh rate if they didn't already. You can download these files over the web and just use the documentation from the titles you imported to enjoy the game, and simply keep the floppies for posterity.