Andy,
This may work and should handle the load for 3.3 too.(OK so it's 3.4v)
I haven't given it enough thought though.

                  5.5V
                   |
                   |---|>|-|>|-|>|--
      -------------o                |
      |            |                |
      \            |                |
      /470         |                |
      \            |                |
      |    10      |                |
 PIC--o---\/\/-- FET                |
                   |                |
                   |----------------'
                   |
                  Vcc to circuit
Regards
Mo