Ford Focus Mk2: How to replace the thermostat | 1.6 petrol

Since getting this Mark 2 Ford Focus 1.6 petrol, I've noticed that the engine takes a very long time to warm up, particularly in cold weather, and also fluctuates a lot while driving. I suspect that the thermostat is stuck open, meaning that coolant is always flowing through the radiator and causing the car to take longer to get to temperature. In this video I set out to change the thermostat out for a new replacement. 00:00 - Symptoms 00:49 - Plan of work 01:35 - Remove power steering fluid reservoir 02:06 - Disconnect battery 02:18 - Slacken off alternator bottom bolt 03:21 - Remove alternator top bolt & nut 03:32 - Remove alternator securing stud 04:10 - Remove terminals from alternator 04:34 - Remove alternator 04:59 - Drain coolant 06:12 - Remove coolant pipes 06:22 - Remove thermostat housing bolts 07:07 - Remove thermostat 07:46 - Install new thermostat 08:00 - Refit thermostat housing 08:09 - Refit coolant pipes 08:37 - Refit alternator 09:07 - Refit coolant drain plug 09:15 - Refill coolant 10:14 - Results