Hi Sue and Craig,
I am sure that some one will correct me if I am wrong, but I believe that the MANUAL gearbox on the main furler is an Amel custom product only available from Maud.
The motorised gearbox on a SM2000 is not Bonfiglioli as on the SN and early SMs, but LEROY SOMER, but this is not what I think Sue is asking about. 
Cheers
Alan
Elyse SM437