Harry Bloomfield expressed precisely :
Harry Bloomfield has brought this to us :
The LED's I already have in stock, so I ordered up 10x 470nF 630v, 10x
220Ohm, 10x 1n4148 and some Vero- board. I'll add a 250mA fuse - I suspect
I will not have much choice but to install that in the common neutral for
the LED's. Rather naughty, but better than no fuse at all.

The live inputs will be fault current limited by the 220Ohm resistors.

L ---- 220 -- 470 -- 4148 + LED (back to back) ---- N

{EDIT] My 6mm superbright LED blew with the 470nF. The 470nF will be to large
a value, amend it to 0.1uF / 100nF 630volts and it works fine.

Sorry, and another [EDIT] of values....

I was using ideas and values found on the Internet, plus a bit of rule
of thumb.

It blew the LED and diode again, after an extended period on soak. So
47nF seems OK at the moment. It was also possible to get it to blow on
surge, repeated switching on and off, so I upped the surge resistor
value 1k2 seems to make it more robust. My present offering is...

L ---- 1K2 -- 47nF -- 4148 + LED (back to back) ---- N