We're off to mainland Europe in July. While travelling there we have to take a number of items not required here in the UK. Depending on country some are compulsory and others recommended.
First aid kit, spare bulbs, empty fuel can, dayglow jackets (1 for each passenger), beam deflectors, fire extinguisher, Warning triangle.
Now, these all take up valuable space. I have some suggestions that you may want to consider, copy or improve upon.
The biggest items to secret away but still have available (for inspection or use) even with a packed Mazda 5 are fuel can, warning triangle and fire extinguisher.
To make space for a few of these at the front, under the bonnet, I removed what appeared to be a venting duct to the enclosed battery. I removed the battery cover and 1 screw holding (near headlamp top) the ducting to the battery compartment. I assume that its purpose was to disperse the explosive gasses produced by the battery under normal running conditions. This left me with 'headroom' to fit fire extinguisher, warning triangle, spare bulbs, first aid and even a disposable camera (for emergencies, evidence and fun). See pictures. You must of course ensure that any of these items cannot fall or foul any part of the running gear or engine. In the picture is Triangle in its box, extinguisher, first aid kit disposable camera in box/foil and the spare bulbs wrapped appropriately and 1 small dayglow jackets. Also a bottle of water can be located here too.
Beware.... careful not to slam the bonnet as your items will no doubt be different sizes to the kit I have, make show you have clearance.
Wait until you see where I've secreted the fuel can....

 

If you look under the rear offside of your Mazda 5 there is a big empty space behind bumper. I had to 'rummage' through my old petrol cans to find a small/slim enough (still 5litre) to fit nicely in this cavity. Then cable tie it by the handle, 2 to be safe. Bare in mind that you will need a knife, cutters or Gerber type tool to cut through proper cable tie (nylon). In an emergency you would look for stone, metal or flint on the side of the road to 'saw' through it if necessary. It is invisible, only you (or someone you run over will know it's there, Ha HA!).
The spout you would keep with the spare tyre or with the jack.
Obviously it is an empty can, but some countries require that you are carrying it.

 

Improve, negligibly, your fuel consumption figures by removing unnecessary items that add to car weight. If you don't plan to have passengers remove (and store suitably in garage or loft) all unused headrest (very heavy). Also consider removing unused carpets (even buy cheaper lighter carpet and replace Mazda 5 logo'd carpet when you sell as these will look great and clean when you refit for sale). The same goes for the cup/ashtray things in the rear, as well as the retractable rear seat cover.

 

I have a 7 seater but never use the rear seats. I have removed the rear seats (only need to undo 5 bolts) and increased my boot space as well as saved about 30kg in weight. The tyre tools fit easily inside the spare wheel space. Also if you are not comfortable with a temporary spare wheel there is now room to fit a full size spare.

Mazda 5 2.0D Sport 2008