Non MCS Installer commissions system and get passed for part P ?
Non MCS Installer has system inspected by MCS Accreditation body
Non MCS Installer now has his paperwork and is a MCS approved installer.
System is now a secondhand system?

or all OK and can be registered with Gemserv.
Depends I suppose on what the MCS accreditation body needs to sign off on inspection!!
Can't be that the system has been commisssion can it, does it hasve to have been signed off underbuilding regs?
When does a system become secondhand?