Just a small observation to add about hermaphrodites. The best sponson arrangement would have been male on the right, female on the left (as viewed from the front of the tank). This would allow the 6 pounder a slightly better forward firing arc due to the location of the sighting apparatus.
I don't know about Mk. IV tadpoles but the Mk. V definitely did have a female conversion.
There is a photo of a female Mk IV tadpole towing a camouflaged gun and limber(?) in "The Landships of Lincoln" on page 69. The photo is captioned as being from the Tank Museum, Bovington. So, yes, there were Mk IV and Mk V female tadpoles.