First about AHP.

Some eps were indeed set in England. But there was one Laurance Harvey-Hazel Court-Patrick Macnee ep that really did seem to be made in England (but wasn't). It was about a sick chicken farmer (Harvey) who had a bad way of making great chicken specimens. God, It was so hard to believe this ep was not actually made in the UK but rather in Hollywood. Macnee made the ep in the early US-phase of his long career. He did a Twilight Zone around the same time.

Hitch was from England originally.

There was, however, a sixth season ep that actually was filmed in England. Not anywhere that famous in the UK mind you. One wonders how we were so convinced it was truly England when we did not recognize the scenery.

Now to OSB.

There was at least one ep set in England. It was about a released murderer who was convinced he was indestructable. I do not think this ep was made in the UK. Just set there.

John Newland was born in the USA.

Now, later on his show Christopher Lee played a German soldier who was magically whisked hundreds of miles away and he thinks it is all an illusion. Having fun with this illusion he shoots his girlfriend (again confident she is not really there). When the illusion ends, Lee discovers his girlfriend really has been ultra-mega-tragically murdered by (If I remember right) a gun just like his. Now, Lee was an Italian-British actor and this ep had other British actors in it. I figured John Newland flew them all to Hollywood to make the ep (TZ producer flew Donald Pleasance from England to Hollywood to make an ep of that show). Actually, what happened was just this. OSB was made by MGM studios and they had two studios one in California and the other in England. They decided to let the English MGM studios make the last like around 12 OSB eps. That explained this weird phase of the American OSB.