exporting before importing for IPR

Is there a way to export a repaired item to a customer and exchange it for their faulty item for inward processing? We want to send a customer a repaired gearbox for a car and they will send us their faulty gearbox which we will repair ready to send to the next customer. We would like to do this if possible with no duty just the same as if we had repaired the customers own gearbox and sent it back to him.

Hi PTU
You can use inward/outward processing reliefs to Import/Export same commodity.
If the importing item is not the one which has been previously exported it Is not possible to claim the relief.
More information on below links:
Apply to delay or pay less duty on goods you import to process or repair
Apply to pay less duty on goods you export to process or repair
Thank you.

You can do this and get . It’s a variation on inward processing known as prior export equivalence. It is a bit complicated so you may be best advised to get some professional help to get set up.

Thank you both for your comments we will look into the "export equivalence" many thanks