well decided to pull the dash out and replace the heater core, had one sitting no the shelf for about a month and been putting it off,
removed the dash, instument cluster, steering wheel, indicator stalks etc to get to the heater, pulled heater unit out and went to separate it, removed the 2 screws, and all the clips, drilled the rivets out of the heater control panel, and still could not get it apart, the freshair/recirc flap was holding ti all together, spent 10-15 mins trying to figure it out, said dammit, reassembled the heater unit, got a 5" grinder out and slit the base of the heater unit out, and then slid the core out, fitted new one in, put duct tale to hold cut panel back in, as it sits pretty much on the floor it is not going to go any where!! refitted every thing to vehicle, i then removed the air cond unit as it is no longer in use, will give room for a glove box, blanked off the old duct and re plumbed heater in, now have hot air and cold air as req,
what a S*** of a job, will not be in a hurry to do that again.

discovered a few new "boxes" under the dash, a radio receiver that id wired into the rover loom, and runs a coaxial lead to the radio, has 1233mhz on it, buggered if i know what that does.

Cheers

Pedro