SCOM 2012 RTM wont upgrade to SP1

When upgrading a clients SCOM 2012 to SCOM 2012 SP1, I was getting the incredibly frustrating error

"Host not found", followed by

A bunch of googling came up with info that didn't help resolve the issue....

The event logs were fine.... so, due to the error "host not found" - I put wireshark on there, to try and find which host was "not found"

Turns out, who-ever installed SCOM 2012 (and made a bit of a mess of it) had upgraded from 2007 - and the old SDK server was still in the registry under 

HKEY_LOCAL_MACHINESOFTWAREMicrosoftSystem Center Operations Manager12ReportingDefaultSDKServiceMachine

 HKEY_LOCAL_MACHINESOFTWAREMicrosoftMicrosoft Operations Manager3.0ReportingDefaultSDKServiceMachine

Since the old SCOM server was long gone, I had nothing to lose, so I updated the values to be the current SCOM server - and away we went.

Simple fix - took a while to find.