Wayne here is the drawing made for cutting the main side. Obviously different for a FV1609 from a FV1611. As you will appreciate it is difficult take measurements for something that is in thin air. The net result was errors of an inch or so as something wasn't right with the angles, giving a deficiency one end & surplus the other
The result was to build the frame & feel happy with that then to cover it & cut it down to shape. Without the skill or equipment to spot-weld & I had no MIG at the time, I cheated by fixing the outer sheet to the wheel arch with countersunk rivets which were eventually smoothed over with filler. I just didn't want to risk melting through or buckling the thin sheet.
Given my propensity for reversing the Pig into various obstructions, the lockers on a frame have proved more durable & easier to repair than a more authentic series of flimsy sheets held together with spot-welds.
Yes various bits of CES & other kit could go in the lockers, no specific space allocations. Unless you keep it under cover from the rain there isn't too much you would want to store in there given the points of entry for water & worse on yours as you have another hinge.
Incidentally the picture of it in red oxide, the top lockers hasps were just from B&Q & are surprisingly close to what was originally fitted. The small side locker is original with its original hasp that is far enough away to pass as being the same. The crudely welded domestic hinges have been criticised, but as you realise when you look at yours these are entirely original fittings that were on the NOS lids I was lucky enough to have.
The bits I had were mainly front wing under locker support pieces & I think perhaps part of the locker internals. There was the top side hinged piece & I think in Reading the main side wall that it attaches to over the wheel arch.
PS You will see my comment to the metal cutter to make the cuts a bit wide in case the geometry was wrong! This proved very worthwhile, even so I was still short along one edge but by tilting it I was able to get full coverage for trimming down. On reflection I should have just order a more basic shape to give me plenty of spare to play with. All I wanted was to have sheets that were of a manageable size that could be fixed to the frame to give support & enhance the quality of cut. Having rigid support like this it was quite easy to cut it into shape with those very thin angle grinder discs.