Timing needs to be spot on, new chains have the mark on them so you can't go wrong, heater matrix being blocked could be whyi ts not getting hit, or the thermostat or the water pump

also make sure the fans are working properly, you should turn the engine off and then spin them by hand first and then remove the fan switch plug from the thermostat housing and, with the ignition on, short the right side pins out and then the left hand side to see if they actually do

finally make sure you fit the lower temp fan switch from the mondeo, it's red rather than the grey one that is standard fit, there is also a green one Whig is halfway in the middle