The 1937 are probably the least exciting (to me) penny varieties - none of them is rare and they are micro varieties at best. The two 1940s are a different matter; the 'common' one is fairly elusive in BU but the other one (rated N in Freeman) is a bugger to get. I was lucky enough to get mine from John Dunkerton of Windsor Coins in the late 70s when collectors weren't too bothered about them.
The 1944 is - as you've found - surprisingly hard in genuine Unc; mine is AUnc only but I've never been either enthused to upgrade or seen one at the right price.
I cannot find a high grade 1946 O N E ' for love nor money. Should you find two in your search, let me know!!
A friend of mine, who has since made an even bigger find that is yet to break the mainstream news, a huge hoard of William and Harold coins.....the hat pin took 6 years to go through the treasure process and was eventually disclaimed and returned to the finder