Hello Johnh,
Yes it's just jumper switch for PAL also make sure it's Buster 11, as I shiped A4000 from the US to Australia (As I could not find one here).But you need new Power Supply as A4000 power supply does not allow you to switch to 110 volts to 220/240 volts as there is no switch for it.
If you can convert a AT PC power supply for the job then your in business otherwise finding 220/240 volt A4000 power supply is going to be hard unless someone on ebay or Amiga User Group in your area has blown there A4000 and are willing to sell you the power supply to you.
The same story is true with A2000/A3000/A3000T Hope that
helps Merv