I'm starting with the bypass then will bleed the system and test at that point. Upon further inspection with diagram in hand (thanks buzz) the top of the valve cover definitely has had coolant running down them from the TB. I pray it's not an HG job. I just did one about 15 months ago, and am not in the mood to do another.

 

Update to the issue:

Found a pin sized leak squirting coolant out and on to the valve covers, which in turn was splashing up and almost it look like a possible leak from the top of the intake housing. THis was then pouring down past the valve covers and off the back of the engine giving me the impression i may have something larger on my hands. Did the bypass, so the truck is mobile, but will properly fix the issue when the part arrives on weds or thurs of this week. Cleared the codes (thanks ultra gauge) power washed engine to remove any trace coolant and she's back to running smooth as silk.. or at least burlap, she is a rover after all.

As always, many thanks for the help.