Taking an iMac to another country

Hello

This isn't in regards to any issues, it is simply a query.

My boyfriend has an iMac that he bought and uses in France but there is a chance that we are going to relocate to the UK.

The UK uses a three prong plug as opposed to a two pin plug; my question is would be able to take his current power adaptor into an Apple store and exchange it for one that works in the UK? Or would we have to use one of those plug in ones that you use when you go on holiday for example?

Thank you for any feedback 🙂