So taking Gbye grey sky's example
"So, for example your fund was worth £100,000 when you migrated and it is now valued at £160,000. So 25% (or £40,000) has grown by £15,000. Convert £15,000 to current exchange rate (say 1.80) = $27,000. So in this example $27,000 is taxable in Oz at your marginal rate even though you will have $72,000 to transfer over."
one step further, if only (say) £5,000 had been paid out of the fund, then as Andrew from Vista comments, is the taxable AFE the total growth in the fund (£60,000) but limited to the amount paid, ie £5,000?