Hey, contact tplink support to figure it out. I dont know what could be the cause.

If they work while in the same consumer unit or in wall sockets but not when they on separate consumer unit, it's circuit wiring issue even though I don't much about your consumer unit.

Update the firmware? And model number? Which LED blinks BTW? Try another location

all tplink are compatible

Did you clone the wireless settings from the virgin wifi to the tplink? If they have the network name, set a different name for the tplink; if they are different now, change the tplink same as virgin...

Re install the camera app or update it. Make sure your phone connects to the same home network (same band, no guest network) , no AP isolation or filtering on your router.