it will be really hard just going by the limited photos alone.
1. It looks like you have two 'tombstone' ammo containers molded on the floor on each side of the angle section of the shield under the Bofors wall mounted ammo box. There really should be seats here for the loaders, attached the the shield just under those wall mounted boxes and protruding outward. The 'tombstones' were strapped to the floor along the side and to the rear.
2. There are cross braces from the mount to the top of the shield that are missing, (at least in your photos) These braces attach to the top of the shield on the side, directly in the middle of the four boxes. The space in between the four boxes should be greater than the spaces between the others, this space is equal to and allows the brace to be mounted between them.
3. The angled portions of the shield at the front appear to be twice the width of the mounted Bofors ammo box on your part. I think this is too long, (or the box is too narrow) as photos show the ammo box taking up quite a bit more than half that wall space, ...which in turn leads to what I see as another possible issue with the two narrow sections of the shield on either side of the gun opening, they are too narrow on your kit part. There were wall mounted scabbards on these wall sections to hold the loaders rifles, and appear to be quite a bit wider (almost twice as wide as you have?)
4. There is shelf/bracket the hangs off the back of the turret, just under the gunners seats, for tool box and other storage.
5. There are two slightly bowed, tubular assemblies on the top of the mount, they act as tilt hoops to support the canvas tilt when installed. It keeps the canvas raised and shed the water to avoid puddling and sagging of the canvas tilt.
6. It appears that you have the Bofors ammo boxes on the side wall, 'stepped'. I'm not so sure the M15 did that as I believe they were all level across, I think that may be an M15A1 set up.
7. There should be a gun travel lock on the cross member just behind the driver/passengers head, centered just above the fuel tank.
I think I see more things but I'm wary commenting when just going by these photos. I don't know if you left stuff out of the pictures or I just can't see things 100%. I would be able to be much more specific if I had many more 'better' photos (or even better yet, the parts in my hand) but you may see that as just fishing for a free kit lol.
I'd like to help more but I'm limited to what I can thoroughly see.
Best of luck with the kit. I know I'd be interested in a few myself.
Build how you like, like how you build.