Logitech harmony + smartthings now wonky in the UK

Help as I’m at my wits end. Origionally both the smartthings and harmony were talking to one another nicely, now, not so. A few weeks ago I setup a smartthings motion trigger to turn on a few hue lights and then trigger a “Watch TV” activity on the harmony which turned on the TV, turned on a set top box, turned on an amp and set all the right input settings so my wife could walk in and hey presto “the TV comes on” and it worked great. Then I got an Amazon Echo and integrated it into the system and that’s when it went haywire (coincidence or not). Now whenever the motion sensor is triggered it now sends the command to turn on the TV constantly, so whenever you move in the room the TV essentially burps a black screen and tells me it’s on the right settings and then the picture comes back, annoying when you have a 4 year old son tearing about the room (incidentally the hue lights are not affected and remain on). So I deleted the echo, and reinstalled the harmony but the problem persists. Any ideas please, and thank you.