I've got a Ka.. It's a 1999S with approx. 85k on it. It's had "advisories" on corrosion on the MOT for the last few years. had a bit of welding a couple of years ago. It's gone in the classic ford places of the sills, slam panel, and around the filler cap too. It's a shame really as it's been a great little car, never broken down even once, it's still on its original clutch and battery - and i have kind of thrashed it a bit - the engine is still sweet as a nut. the alternator has started squeaking a bit at cold but that's not a biggie. It's fun to drive (especially with an extra 50bhp

) and comfortable. It's also very easy to drive. But i noticed even going back to about a year after i got it (late 03) that there was nasty looking rust underneath..
I've always been a fan of fords, i've owned one mk1 fiesta, four mk3 fiestas (1.1, 1.6d, XR2, then XR2 i put a RST engine in), a mk2 escort, two mondeos, an XR3i, and this ka. Tinworm has always been a problem for fords, which is a shame as they tend to do the rest of their vehicles very well. Even so i'd rather a ford than a vauxhall - just don't like them at all - IMO the last really good car vauxhall made was the last cavalier (had three of those too) - I tend to keep one daily ragger, one fun car, some van type vehicle(tax exempt landie), - these are kept for some time.. but i've usually got a car i'm doing up, driving around for a bit, then selling on for profit - fords have always been great for doing this. the trick is finding one that is unrusty (garaged and kept properly cleaned) and then clagging as much rustproofing as possible all over it. I had planned to do this with the Ka - every panel not directly visible coated in rustproof, but by the time i got around to it, there was that nasty rust underneath.
Hence i've got a (galvanised, unrusty) 306D to replace it. I hate rust so much it's all i can do not to spout a great deal of northernerised obscenity within this post lol. Rust is the only thing that.. isnt worth trying to fix once it gets hold of the main shell of the car - it'll come back eventually.
Dunno about you guys but if i had a mondeo as new as the OP's that had the rust that it had, i'd be DEMANDING new replacement panels. Ford, if i remember, were funny about the warranty on Ka and Fiesta from the late 90s, early noughtys,.. if it had a water leak into the cab (and a hell of a lot did including mine) it wasn't covered under the warranty. This combined with the rusting problems are making me seriously consider that when this 306 goes, i shall be replacing it with something probably from our friends at VAG.
EDIT: you might say a 1999 car should be rusty at 85k.. but.. no. It's very dissapointing when you consider the 2000 306 i have with 102k on it has no rust. The Ka has been showing signs of major corrosion since 2004 when it was 5 years old. Not what one would expect out of a modern vehicle from a supposedly reputable manufacturer like ford.
EDIT2: that'll teach me to say "its never failed, never broken down, on its original X part" - Literally an hour after i posted this, I went to the Ka just for a quick jump down the shops, and.. hey presto, it wouldn't start, and the starter motor sounded WELL weak. Oh well i guess the battery is 9yr old.. its very, very cold up here in west sheffield this morning, but the sun is bright now. Knowing that a battery is basically a chemical reaction, i pushed it into the sun to warm up a bit.. 2hr later it started first time. I reckon the battery is on its way out.. I know what kills batteries gradually and would expect such a symptom based on this gradual degradation of the rubber sheets between the elements of the battery. It should be ok for a bit as long as its kept reasonably warm.. Now its a case of morals.. Do i sell the car knowing it wants a new battery imminently, or do i hunt out a 2nd hand battery in working order.. or buy a new one for it.. it's being replaced anyway..