I have had my Poseidon regs for years in UK where servicing was easy to come by, now in USA (TX) I do not have a local place to do the service so will do it myself (I have done other regs, just not Poseidon). My question is, findingthe model number in order to getthe correct service pack- is the model number on the DIN ring? 39xxx etc? Is there an online model/ serial number look up function that anyone is aware of? Thanks in advance.