THE MAN IN HMRC WHO RUNS QROPS GAVE ME THIS INFORMATION (APRIL 2011):

Withdrawals within the first 5 years of leaving the UK

Payments will be reported within 5 years.
If a withdrawal from a QROPS is consistent with the UK pension and rules, then there is no problem in making a withdrawal within the first 5 years.
A tax-free lump sum of 25% can be taken within the first 5 years if the UK scheme would have allowed it. The remaining funds must be used to provide a lifetime pension.

Return to the UK

If you return to the UK, then benefits from overseas will be subject to UK tax. If the benefits suffer tax from abroad, then this will be taken into account. For example, the UK wants £30 tax but you’ve already paid £20 abroad, then you’ll have to pay only £10.