Hello Gareth
The Originate attribute compares prefixes based on if they have originated on the local router. Specifically, if a route is learned via a network or aggregate BGP subcommand on the local router, or through redistribution from an IGP again on the local router, then it is preferred over prefixes learned from other BGP routers.
The Origin type attribute has to do with if the path was learned via IGP, EGP, or if it has been redistributed into BGP (incomplete). This is more thoroughly described in the following lesson.
Now these two might seem similar, but remember, that the Originate attribute is looked at first. If that attribute is the same between two candidate routes, then we go on to the next attribute in the list. It is possible for two prefixes to be “tied” when the originate attribute is examined, but that tie can be broken at the origin type attribute.
I hope this has been helpful!
Laz