youve missed a bit!!!!
More good work! Is the heater something similar to this?http://www.carbuildersolutions.com/uk/all-in-one-compact-car-heater-with-vents-and-valveI'm sure Smiths made a generic heater many moons ago that Land Rover used a version of as a standard fit as did many other manufacturers before heaters became standard issue in cars. Who knows, it may have been a dealer option when yours was first sold and as such could be considered original.I doubt the supplying dealer is still in existence now and even if they are, the chances of 35 year old records being kept or the employee that fitted the heater being there are pretty remote so i'd just enjoy warm hoofs and think of it as original as it was there from new.
Going to fit an early YJ roll bar mainly for the convenience of having decent modern seat belts as well.