A Mark IV yes, but not under construction. It is already marked with Home Service or training numbers so possibly at Bovington, and undergoing maintenance. The HSN starts 14, but its not 141, 144 or 148 as the last two digits on the serial number are wrong. I'd expect the serial number of this tank to be 4039 but can't be certain.
Nice photo anyway and one that's new to me. Thanks for sharing.
