Does this work (swap trick without mod chip) effectively for most people?
ANSWER: Not in my view. Some people shove a knofe in the disk tray to trip a release and pop the disk out! Madness.

Is it likely to ruin our machine? it sounds pretty destructive ...
ANSWER: YEP!

also, if you try removing the silver disc and using it, and the whole thing doesn't work, is it impossible to restore the PS2 to how it was before?
ANSWER: YEP! Well you can get it repaired of course.

if anyone has some suggestions/comments on this whole thing, that would be much appreciated!![
ANSWER: Get a modchip. If you need further info on how toproceed down the path of chipping and making game backups, just say so, or search my earlier posts under the heading "NEWBIE".