Don,
not side hatches.
I meant the underside entry hatches, with the integral, telescopic ladders.
The rear hatch had an internal hatch cover, which was hinged and opened up, and to the right
side (starboard) , and was a one-piece cover, normally made with a "corrugated" surface on the underside, and "flat" on the internal side, which formed the floor over the hatch opening in the rear fuselage.
This is (just) visible in one of the photos I took of the ex-RAF/RCAF Mitchell II when it first arrived at The Fighter Collection, Duxford, UK, back in 1988.
The first photo is looking forward, just aft of the rear entry well, with the yellow-painted internal hatch cover shown arrowed, at right.
The second photo is an external view of the same rear entrance hatch, showing the drop-down hatch cover and telescopic ladder, with the arrow indicating the position of the internal hatch cover.
Note that the seats are "modern" additions. At the time, this aircraft was In a fairy dull, weathered, bare metal finish, but was eventually painted in an accurate, authentic RAF scheme as "Grumpy" (with a teeny tiny input from my research), which it still wore when it departed from Duxford, UK, for the US around late August 2009, and I think it still wears the same colours today.