Hello Ritchiec80,
That is most likely the case. To change the device, you would need to have a service engineer to come and reformat the printer.
I recently bought a 2nd hand 7500dn, when it came to replacing the toner it seems that the machine might be on metered toner rather than sold. When I put the cartidge in it always asks for a different version with a different code rather than the regular sold UK version. Is there a cheap way I can find out if this is the case without getting an engineer out? I'm in the UK.