Any British light will since the switch wires do not run with a neutral will have some capacitance or inductive linking so unless the lamp has some circuit to allow a small amount of current to flow without switching it on will flash or light dim, a little like the 4 - 20 mA sensors used in industry all LED lights in the UK have to let a little current flow without lighting, how much however unlike the 4 - 20 mA is not laid down, so varies bulb to bulb, the switches normally state the load needs to be 5 watt minimum which one would expect means 5 watt total, however I have found bulbs under 5 watt even if 5 are used so total over 5 watt they don't seem to allow enough current to flow without a load capacitor. So G9 bulbs are a problem, but found GU10, E14, and BA22d bulbs work OK.
It seems there are two issues with LED bulbs, one is flashing when off, the other is a flicker when switched on, I am not sure what causes the flicker, when on, just know if bulbs over 5 watt are used it does not seem to happen, only bulbs under 5 watt seem to have a problem. I use wifi light switches without a neutral and they seem to have three problems.
Two already listed and as long as bulbs over 5 watt are used it seems to be avoided, clearly if the electronic switch dims the light as well, then if 50% dimming the bulb needs to be 10 watt so still 5 watt when dimmed. My electronic switches are simple on/off, the third problem seems to be EMC, using a couple of sockets and switches there was no problem, but as the number increased to 21 I started to get a problem with lights having a mind of their own, switching on/off when not set to switch on/off, so have needed to remove two light switches, this has resulted in a socket which was also doing it's own thing to start to behave its self.
The room with G9 bulbs has one quartz bulb, which seems to cure the flicker on all bulbs.
I use MiHome Energenie, there is also a forth problem, any power cut and the units remain off after power is switched back on, so when the plug in ceiling rose had a problem could not work out if it was the switch or ceiling rose, so fault finding is a problem, only way was to refit the flick switch until fault found.
But in general not had problems with BA22d bulbs, or E14 bulbs in a chandelier one has 5 the other 8 bulbs, did have a slight problem with GU10 but simply swapped bedroom bulbs with kitchen and flicker stopped, only the G9 required a 4 uf capacitor across bulbs, and even that only stopped it not switching off, it did not stop flicker, had to fit one quartz to stop flicker.