Yeah, but it's just the name of the item.  That's a pretty trivial thing to substitute in, and it's there in the room - not much difficult to say "ah, you have found my key" or "ah, you have found my gem" or "ah, you have found my bracelet".

Agreed, except in the case of Dickon's quest, where he had to convince Brother Mace to drink a bottle of brandy, which happened in level 2. This would be more difficult to resolve if these levels were 'moved about'.

The whole 'doing a favour for someone' thing in series 4 is much the same principal as the steps because it was also a feature of every quest. Every team would, of course, get the Eye Shield! I think it was a device to ensure that the team would get a spell of some sort to use in the Final Conflict.

But surely the idea of the self-contained levels is that any level 1 can be used with any level 3. However, the item mentioned in level 1 (not the main quest item, the item that the character gets given the Eye Shield for agreeing to help) has to be there in level 3, so this changes things.