Ahh, of course - I merely (belatedly) spot these things, whereas you actually do something about them .....
The gender was certainly 'fixed' at the factory - indeed, it was established by Contract. Coventry Ordnance, for instance, was contracted to build 100 Females, numbered 4551 to 4650, and that was their only order. Likewise, Armstrong Whitworth was only contracted to build 100 Males, numbered 4001 to 4100. A number of the original Contracts still exist at the National Archives in Kew (as an ex-Accountant I find them particularly interesting, but that's just me
). I've got a complete table of Mark IV builds if anyone wants to know who built a particular tank (although I can't publish it for copyright reasons
).
I've always suspected, but not yet proven, that the male / female sponsons were easily interchangeable, as that's where the hermaphrodites / composites came from. I'm not aware of any contracts to actually build them, and the available pictures (especially L Battalion in Cologne in 1919) show pretty well an even number of tanks (Mark V's) with male sponsons on the right against those with male sponsons on the left. That suggests a workshop change, although I've still got no idea why they actually did it !
I'll leave you to it, then .....
