Right, need to overhaul the underside of my car, Will need to clean it sort out the beginings of the dreaded tin worm, spray it back Java blue then some form of clear coat to protect it, but what products are best for each job?

Cleaning - Gunk?
Rust - hammerite?
(Will primer then paint)
Top coat - Normal Laquer or is there a clear underseal?

anything I need to take into consideration?

 

So far ive found:
petrol's best for cleaning away dirt and oil
Killing the rust - Bilt Hamber looks like a great product, Deox C gel - paint it on then leave to react not tried it yet but know people have had some great results with it, as goes for their version of waxoyl.
Also can't recommend a wire cup on an angle grinder enough if you're planning on taking the underseal off and down to bare metal.