You got it in one MtheGM! Perhaps this one will be a little less ambiguous.

Australian brain transplant joke.

An Englishman wanted to become an Irishman, so he visited a doctor to find out how to go about this. "Well" said the doctor, "this is a very delicate operation and there is a lot that can go wrong. I will have to remove half your brain". "That's OK" said the Englishman. "I've always wanted to be Irish and I'm prepared to take the risk".

The operation went ahead but the Englishman woke to find a look of horror on the face of the doctor. "I'm so terribly sorry!!" the doctor said. "Instead of removing half the brain, I've taken the whole brain out". The patient replied, "No worries, mate!!"

Cheers,

Andrez