OK so I've got my zed up on stands, have had a good go with the wire brush, and am about to wax oil the underside and was wondering before I get spraying whether there are any areas that I should avoid or any areas where I should be particularly generous? Also am gonna fill the sills but with what? Oil, cavity wax, wax oil, or fertan (rust converter)? Or a combination of those?

I used cavity wax for my sills. I found Bilt Hamber dynax s50 got some of the best reviews, so I went with that. It comes in an aerosol with a long tube and it's really easy to use.

Sounds good, is that something I can get at the local auto's? I assume it has rust inhibitors in it?

I got it direct from Bilt Hamber, I don't think I've ever seen it in local motor factors.

http://www.bilthamber.com/dynax-s50

+1 for Bilt Hammer, excellent reviews and easy to use (make sure you buy the nozzles to fit on to the cans to get to the cavitys) Easy job to fill the sills.

Thanks chaps. Looking online. Will a 750ml aerosol done whole job?

I used two 750ml aerosols, there are a few sections inside the sills that need to be treated. I got the lance all the way around the rear arches too.

How long is the tube that comes with these Ash? Are there plenty of holes in the sills to get it all along thoroughly?

Probe is about a metre long and mercifully just fits in the holes underneath the plastic sill cover under the door without even having to remove the plugs, you just slide them over. I think that covers the outer sill. If you want to cover the inner sill I think you need to uncover the tape covered holes under the carpet and wangle it in there. Also if you remove the plastic wheel arch linings at the front there is an access hole under a rubber bung which allows good access to the front end. There seems to be like a middle sill though aswell.... Only jesus knows how to get in there..