Howdy people!

My LandRovers being welded up at the moment, when it comes back I would like to protect it from rotting as fast as it did and would like to know what products to use and in which order.

I have about 4litres if Hammerite already, realistically i'm looking at protecting the chassis and underneath, inside the chassis and sills and also the inner boot floor.

As an obvious guess, it seems like I should want cavity wax for inside the sills and chassis, but what should I use for the general underneath?
Someone has suggested 'shultz' to me but have no idea what it should be used for.....

Should I jetwash the underside, let it dry then apply?

Its cost me aprprox £600 in welding so far so would like to preserve it while its fresh!

Thanks in advance

EDIT:

Forgot to say that the Landy will be used for offroading, wading, generally getting covered in mud and muck, due to it having a snorkel and wading gear fitted it can go very deep in water (bonnet submerged) hence wanting to protect it!