Jacko
Crikey - I can't find anything in what you just wrote that I disagree with. I glad you said "some" heavy armour could be shed and not all, as some have proposed......
Many infantry units are equipped with Warrior Infantry Fighting vehicles. These protect the troops until they have to demount for the assault. They also provide fire support with the 30mm cannon that they are fitted with.
Tanks, whilst perhaps not needed in the numbers they used to be (mind you we deployed 160 or so Challengers in Gulf War 1, how many did we deploy last year?) were/are attached to Warrior equipped units to protect them from Iraqi armour.