foreign pension scheme

My client is a UK citizen who derives his income as a self employed agent for a German company - the German company is not registered in the UK. The German Company pays pension contributions into a pension scheme registered and administered in Germany on behalf of my client and my client pays in the same amount. I am assuming (though I have thus far been unable to find out) that the German Company is receiving tax relief.  My client is a higher rate tax payer. I am uncertain as to whether my client will be able to claim tax relief at all, or whether on his higher tax rate in excess of base rate relief or whether on the full higher tax rate (if contributions are not grossed up). Has anyone else experienced this situation? And can anyone give me any guidance?