hi james i have had a zetec engine with the same symptons as yours, it would not start when cold your compression figures 100psi seem a bit low have you tried doing a compression test after you have run the engine for 10 minutes i was getting around 140psi after i had warmed it up
i used a good engine flush then took it for a 30 mile trash changed the oil to the correct grade 5w30 it was all ok after