Sounds like you have had a frustrating day today Andy.
I know how bad it feels to take one step forward & take two back
The only thing that springs to my mind is, are you sure you have the right sender unit for the gauge ? ( I suspect that you bought them as a set, complete with senders )
Perhaps the sender is Air locked, causing a false reading !!
I do know that the CVH engine does run quite hot but don't know that the oil temp shoud be
Hope you get it sorted soon mate
