Using Peters solution though C1 would be a high voltage but small ie
about .1 uF cap for a couple of mA and C2 would be a low voltage cap. In
your circuit Reg wouldn't you require a high voltage high capacitance
capacitor for C2 which would be relatively  quite expensive.
Jim
>>>> how about this solution
>>> http://www.vertonet.com/members/pvh/scr.pdf
snip
 > Peter's circuit is slightly different from the circuit I used. In
  >my application C1 was omitted. R2 was between C2 and D5, i.e.,
  >C2 would charge up to peak line voltage and R2 limited current
  >through D5. Reflects the reality that if you only need a few mA in
  >a very price-driven application, and you don't have a user interface
  >to isolate, power resistors are cheaper than transformers.

>  My reply to the original query outlined the disadvantages. It's
 > certainly not a universal solution.

>  Reg Neale