Hi, the way over and understeer was once explained to me was in terms of grip. When understeriing you have less grip in teh front than the rear and vice versa for oversteer (unless of course you've deliberately induced oversteer with a heavy shove of the welly.
) So I always come back to this concept when sorting suspension.
Sure you can improve on your tyres but you may still find a differential in grip between front and rear.
In this instace you don't really want to reduce grip in the rear so that leaves improving your grip up front. Some possible options worth considering:
softer front coils (haven't got a lot of experience with Escorts but other might advise whether 220lb is on the high side or not);
raise front tyre pressure (perhaps then lower the rear as well - to reduce grip);
increase your negative camber (via your adj strut tops -try this before spending extra money on adjustable TCA);
check Ackermann angles given you have been playing with the front suspension (if you are lifting a wheel in the corners then Ackerman is not a factor!).
I recall front sway bar size is also a contributing factor but for the life of me can't recall what you should do when experiencing understeer - certain someone else will know.
But the grip concept helps me sort out which bits/end to focus on first. Also,only change one thing at a time. Try it then adjust/add from there. Also start with the cheap options first, eg tyre pressures, etc.
Apologies if you know this.
Edit: should have added, it might also have something to do with your driving approach to and exiting the corners. Again keep the grip concept in your head.