In case it is any help to MKV (MK6 too I think) owners... applies to UK models.
My instrument panel battery warning stayed on no matter how long the journey or whether with lights or not. All else seemed fine and at first I didn't think it could be the alternator. I did a voltmeter test at the battery and the alt seemed to be working fine (getting 12.6ish volts on tickover and about 13-14v at around 2000rpm. I thought the alt was okay so began a long search for something else (you guessed it.....I wasn't sure what I was looking for but had vague notions of finding a broken or loose wire or connection). Then the penny dropped and I realised I hadn't done the volt tests fully, i.e. I hadn't turned on the lights, heaterblower, rear screen demister etc. with the engine running......doing this I tried the volt test again and at 2000rpm the alt was delivering less than 12 volts. Time to replace the alternator ! Removing the alternator was a nightmare!
If you are condemned to do this......the following may be of some help:
Put some plastic sheeting and dustsheets etc under the car before you start (unless you want to spend Sunday cleaning your Dad's driveway or, if you're lucky to have one, your own ! Reason ? Read on.......)
Follow Haynes manual as far as you can, making sure to disconnect the earth lead from the battery (do you have a note of your radio code ?) You might leave disconnecting the wires on the alternator until you can get better access to them with the alternator partially dislodged. Take a note of where the red, blue and green wires go.
There is not enough space to remove the alternator without disconnecting the power steering to pump hose. Don't, as I did, get an armpit full of steering fluid (assuming you are also going to be crawling around on your back) by trying to save as much fluid loss as possible by plugging the hose....lose the fluid, all of it, into a bowl. Be prepared for some fluid leaking from the pump. There will be spillage.
Even with the ps hose disconnected and tucked up to the left, away from the alternator, I still couldn't get the alt out. Fresh in my memory is the sound of my own swearing and cursing (and probably the neighbours'memory too). I didn't find any reference in the Haynes manual as to what else to try...it may be in there but I didn't find it. So I got brave and decided to remove the two 10mm bolts which hold the radiator cradle/sill to the front crossmember (you'll find these tucked up and above-left of the horn assembly). The cradle drops a couple of inches which is just enough room to wiggle the alternator out of its dark hole. (Disclaimer : I don't know if any damage is done to other components in doing this.....all I can say is it worked for me). Be careful not to crunch, split or distort any of the coolant hoses (the rad may well get a bit of scuffing and you might need to use a wrench to turn the lower coolant clip out of the way - this kept catching on the alt as I was trying to get it out) and keep a close eye on the brass power steering pump union which also gets in the way.
Refitting the new alt required the adjuster bar and bolt to be fitted to the alt first. The belt was tricky to locate, my version having the later grooved belt and pulley system (1994).I didn't have a spanner large enough to fit the adjuster nut so I used a length of wood wedged between the alt and the ground til I had the required tension on the belt. I could then tighten the bolt which passes through the adjuster and all the other bolts.
Don't forget to reconnect and tighten the Power Steering hose to pump and refill the reservoir with new fluid..... and reposition the coolant hose clip if you moved it off the hose and onto the rad.
Haynes says that Ford fitted several different alternators to the Escort. You may find that your model comes out and goes back in easier. The casings do vary in width and design although, clearly , they all fit and work. The factors I use (Cliffords of Brighton, Sussex.....Excellent price, service and help....always, has been my experience)said that the old unit I presented them with was listed for a Fiesta Van and Combi.
Hope the above helps somebody, sometime. Good Luck !