If you are having problems closing the storage flap, have a look at the holes that
the catches go into. You will probably notice a small amount of swarf around them.
Use a sharp blade to clean up the swarf. The lid will now close properly.
Storage Flap Rattles
Open the storage flap and check the foam rubber stops on each end.
They can compress allowing movement of the storage flap.
Replace the foam pads to take up the slack.
Hobby shops sell sticky backed neoprene sheets that will do the trick.
Alternatively you can try wrapping the catches with electrical tape.
Try 1 wrap at a time until it closes tightly.
The Storage Area Contents Slide Around
Well, yeah, they will slide around. The first thing to do is line the inside of the flap with
something like neoprene, foam, felt, leather, suede, acoustic carpet etc. This will help a bit.
Then you need to secure what ever is in the storage area. By far the best way to do this is by using sections of foam. Upholstery foam can bought as offcuts from places that sell material
and upgholstery shops. You can also salvage foam used in packaging.
Foam can be cut with a knife or with a hot wire to any desired shape.
You could also make a custom holder using expanding foam, sounds messy eh!. In fact, no.
Get a bin liner and lay it in the storage compartment, spray the expanding foam inside the bin
liner all the way along to about 1/3rd the depth. Tie the bin liner bag closed and shut the lid.
After a few days you should have a fully set mould of the storage compartment.
Take it out of the bin liner and carve holes into it to store your stuff.
This is all in my head so might work, might not, if you try it, let me know.