Aredwood:

 

Be cheaper to just get a capacitor from Jaycar most likely. And I would doubt that someone making snake oil devices would ensure that the components they use have the relevant approvals for connection directly to mains.

 

Be cheaper, easier and probably better to just stick a CFL into that one socket. That is all we did. The 2 lamps that flashed were in areas where the lamp was rarely used, turn on for short periods, so any "savings" from having an LED lamp there were almost nil anyway.

The above solution is safe, electrically complaint, easy to do and works.

 Are these LED's hard wired or socketed?  I'm guessing you've got a crappy brand of LED lamps?  Some brands will come with better drive circuity and don't have this problem

This guy frequently talks about the issue in his many LED lamp tear-downs: https://www.youtube.com/watch?v=3EYE9tpv5R0

if its a 70s house its more than likely livened at the lights, if its a 2 way circuit you will have the same problems, its due to the induction in the cables in the 3core or the switch wire if its livened at the lights. the easiest fix is if there is more than one lighting socket on the circuit is to put a incandescent lamp in

You need to fit a pull down resistor between the Neutral and the switched Active which feeds the lamp.

I have fitted that on two lamps which had the same symptom, flickering when off.

Resistor value 100 k.Ohms 2 Watts.

Basically the resistor is in parallel with the LED lamp.

Interesting. I have a couple of LED lightbulbs - they don't flash but they emit a very dim light for a couple of minutes after turning the switch off - as if it was a dimmer. They then turnitself off completely.

If it is a buck powersupply then one of the lamps on the circuit will often remain dimly lit when off. Just shows how efficiant LEDs are that they can light on a tiny amount of leakage that wouldnt even move an analog multimeter.