Scanning the system is the first step.

Unfortunately Very few scan tools except the Bentley / Rolls-Royce one will get into a Seraph I'm afraid. Later BMW cars yes.

Check that the cables under the seats haven't been pulled out or a too tight. Valeting etc.

I just checked my scan tool and I have a Rolls Royce option

so anyone with a good professional scan tool will be able to pull codes for you....avoid the part stores