About this detail of the Tiger
The "Initial" Tiger had two pistol ports at the rear of its turret. For submerged travel, it was necessary to seal them. Two removable plugs were provided to do this.
This Rye Field kit provides two plugs (part R7). Rye Field tell you to glue the plugs into the ports, in this extract from the instructions. But this is wrong. A plug stored here would prevent the rapid use of its port. The plug would never be needed in a hurry, so there was no point in making it so accessible.
We don't know where these plugs were kept in "Initial Tigers" but they were probably in the turret bin or with other general storage.