fixing points for shelving/racking in back of the disco?

right, i want to build a floor to roof shelving unit in the back of the disco to safely store boxes of tools, recovery gear, cooking equipment etc.
i`m making it out of ply and will cover the whole thing in carpet to match the interior, but where/how shall i fix it to the floor and roof? having a dog guard would obviously make life easier, but they aint cheap and work is very slow at the mo. any ideas?

Floor should be easy enough to make brackets up out of bits of angle will have to take a look at mine and try and come up with an idea for you shouldint be that hard famous last words

just have to keep an eye on the stuff beneath the floor i guess

I have the floor in my 90 hindged at the front so I can lift it to get to the area under/between the wings etc. I then have the shelving and boxes up each side. The floor is on a metal frame and has a reinforcement bar along the back to suport it between the wheel arches, but I guess on the disco you wouldn't need this.

what i`m aiming for is a unit to take maybe 4 of those plastic boxes, floor to ceiling. i have to keep one of the dickie seats for the kids, otherwise one would have to walk! i think my main problem would be fixing at the top, as i say if i had a dog guard that would solve the problem, but they`re expensive and i cant afford one with all the stuff i need to do to get the disco back on the road and work being non-existent at the minute.