Definately head off. Pistons go back in from the top! Head on PMSL - I'd like to know how you're going to get the rings compressed

Which zetec is it and on what car? Also what mileage?

Mondeos are a b***ard as the subframe has to be moved because the sump won't come clear of the subframe because it gets stuck behind the oil pump and fouls. Escorts are easier.

Even if you get a slightly lower PSI reading on the comp test it can still be rings (if it proves that's your problem). I've just done one that was 75/1 75/2 65/3 75/4 and the bore was buggered. Fortunately a honing and some ring seal cured it so it wasn't majorly bad, and I did it with the engine in.

Ford as a rule don't do a rebuild and specify a new bottom end as they don't machine well apparently.