I've glued and screwed mine to the ply lining and also to the van in places where it's double-skinned steel. The glue helps a lot with stopping it pulling out, either use wood glue or Sticks Like Sh¡t. Mine's mainly made of 2×2, plywood and four inch screws.
The Nilfisk is great, got a bit noisy when I got some water in the motor once and you'll find that the switch will give out after a while, but it's just the rockers inside that seem to dislodge, take the cover off and it's an easy DIY fix. Fantastic vac though, very happy with it.
The tubs don't fall out because there's a small lip about quarter of an inch high on the front of all the shelves, and the ones sitting on top sit slightly inside the lids. You can see the lip on the top shelf of the passenger side sliding door shelves, this is on all the shelves inside the main part of the van.
Here's my inventory:
Main tool box
Soldering box
Tool box for lesser used tools
Small box of cores
Dust sheet box
Immersion box spanner
Hosepipe
Lead light
Foot pump
Hand saws
2' level
4' level
6' level
Dustpan & Brush
A few empty buckets and drip trays
Making-good bucket
Rubble bags
PPE box
Clip boxes (15, 15 double & 22, plus boxes for their spacers, 10, 15 & 22 nail clips)
Rustbuster C/H Dosing Vessel
Large o-ring box
Filler
Plumbers Mait
Various tapes
Sealants/caulk box
Silicone gun
Rubber mallet
Gas powered soldering iron with accessories, in a box
Two boxes of random bits
Box of assorted holesaws 20-160mm
Oil servicing box
Electric fan heater
110v extension lead
1¼" fittings box inc a couple of traps
Compression box
Consumables box (spare flux/solder/L55 etc etc)
Small-bore fittings box, also has fuses, nylon washers, tap revivers and common small-size boiler spares)
15mm end feed box
22mm end feed box
Repair boxes 1 - 4 (those A5-sized ones you get in most merchants)
3' Crowbar
Cement mixing paddle
Manometer
Inhibitor
Cleaner
Freeze kit
Short steps (get me up about a metre)
Bungees
Leak detector/air duster/other gas work bits
Dyson DC26i (VERY useful compact vac for servicing work and light cleaning)
Testo analyser (not pictured as it was post-photos)
Box for 1½" fittings, also contains a few 2", a couple of float valves and a siphon
5.0 kva transformer
Jigsaw
36v SDS+
36v Combi
4.5" angle grinder
Screwbox
Cordless pipe cutter (don't use it much but useful on big installs)
4kg SDS+
240v extension lead
Kettle
Gas-powered kettle (hey, there's not always power on site...)
Teabags/water/milk
Wet'n'dry vac
Compressor
Circular saw
Bosch GOP in L-Boxx
10.8v screwdriver, torch & impact screwdriver
Servicing toolkit
Jaw Dropper tap spanners
Drill bit box
Box of wood chisels
Holesaw kit (another one!)
Stopcock key
Tub of Big Wipes
Laptop
Full LED interior lighting so I can see it all in the dark
Any more questions feel free to ask!
