Welcome Mat!!!
It sounds like a great upgrade coming

.
Can't wait to see some pics bet your getting excited and counting the sleeps...
I have listed some things I check when picking up a van.
Hope this helps out

!
Exterior -
Awning (Roll in, out, remove legs from van and stand them up, how much tension and roll back in)
Annexe (Setup, packup etc)
Gas system (How to switch bottles, operate stove, gas bayonets if you have them)
Beds (How to drop, close and securely lock with fly screens)
Breakaway System (Make sure you know how to connect to car for safety and operation of breaksafe)
Spare tyre (Where is the jack, bar to spin it up and tyre iron and how to get the spare off)
Tyres (Nitrogen filled how to get replacement air if it goes flat, can you fill them up at a servo??)
Drop Down Jacks (Where is the rotator, how to put down and up and best way to level van. Also check you have a leveller in the van they usually give you one)
External Shower (Working and how to operate)
Brakes (Brake controller setup and working correctly and how to adjust)
Gas Bayonet (How to connect, fitting needed, where they are located)
Hot water (Turn on / off, Change from Gas / Electric)
Trunk door (Where they are located and how to operate some are tricky like the hot water one)
Picnic table (How to operate)
Water (Turn valves on water tanks to change from tank water / mains water)
Solar Panels (How to operate, where they are etc)
Cleaning the van (How to wash, with what products etc)
Water fitting (How to connect mains water, fitting required and type of hose required)
Power 240 input (How to connect power to the van)
Antenna (How to connect antenna to the van and what socket is required)
Waste hoses for shower and sink (Does it have the two into socket drain if its a shower model, where to connect, waste pipe etc)
Roof (How to undo latches, how to adjust them, what is the right tension adjustment for them)
All exterior lighting working (Annexe light / Indicators etc)
Interior -
Battery (What to have switched on when driving so battery charges)
Roof (Single operated procedure for putting up and down)
Toilet (Remove waste tank, refilling waste tank, refilling wash tank, flushing, using the unit hole open or closed big debate

)
TV Antenna (How to switch from powered roof antenna to side wall antenna)
Stereo (How to turn on off, switch speakers if you have outdoor speakers)
Bunks (How to collapse, safe for travelling, ladder security and placement)
Water system (How to use water filter, hand pump tap, mains tap, where the water pump is, is it plugged in and working, hot water working to shower and sink)
Microwave (Plugged in and working, where is the manual etc)
Stove and Griller (Plugged in and working)
Air con (How to turn on, cool, heat etc and if it is roof mounted how to operate the remote)
All drawers / cupboards (Make sure they have all screws in them and open close)
Windows (How to open and close everyone)
Locks EVERY SINGLE ONE (Make sure they all work and all keys have a place to go)
Bed Converter (How to convert bed)
Power Points Internal and External (Where are they and are they working on 240 and 12 volt. Take a car phone charger and a house charger and plug your phone into all sockets with both chargers and make sure they have power)
Range Hood (Make sure working, how to operate)
Light switches (Make sure all working and have something they operate)
Fuse box (Where it is, what to replace and when)
Battery (Where is it, plugged in etc)