I am keen to learn to do as many spannering jobs myself if I can and replacing the headset is one of the last on the list
Commendable.
My best advice, buy a headset press. I did the ‘bodge’ insertion method for years and it generally works fine, occasionally it just doesnt work and causes damage to either the cups, or the headtube.
I bought a 2nd hand press for around £12 and its been used dozens of times since – and presses those cups in like a finely lubricated charm.
PVC tubing / copper tubing split to look like removal tube above would probably work admirably for a cheap removal option. Again, I used a flat blade screwdriver for years – and as a result damaged numerous cups. Mainly aesthetic damage to the lip, but still, looks half arsed, becasue it is.
You can buy the proper tool for what, £10
2 great tools to own that will last a life time and pay for themselves after a couple of uses.