Jim K wrote:

got 3 homeplugs on a home network -

when (for testing purposes) I plug a fourth in to a socket near where
an existing homeplug is plugged in, one of the other distant homeplugs
stops working properly (IP cam - no picture). But if I plug the fourth
one into a socket further round the *same 240v circuit* as before- all
is well.....???? any clues/thoughts please?

Are any of the homeplugs in sockets that are spurs (or 4way extension
leads) rather than directly on the ring? sounds like some sort of
reflection issue ... after all the mains is acting as an unterminated bus.