Reilly ace of Spies

I don't know for sure, but since most of the cast and at least the crew that I checked on were all British or Irish, I think it's a good guess that most of the location shots were in England. Since it first appeared in the U.S. on PBS the next place I would go looking for more detailed info would be WGBH/PBS Boston which seems to filter British TV productions onto American channels. Hope this is helpful to you.

Looks to me like most of it was filmed on a stage set with some very good background "masks". I imagine the outdoor scenes; what few there were; were filmed in Scotland or Ireland.

I was watching the DVD the other day, and locations in Malta, France and England were mentionned. An amazing production all in all.