Right then, third game done and dusted. Some more harsh lessons have been taught... and hopefully learned from

Would have loved to take pictures, but unfortunately my camera is currently on an overseas holiday with my GF.
As for the magic item question, I challenged Chris about it, armed with a print out of this conversation as a backup. He would have none of it (quote: Just read the bloody rules.) and quickly proceeded to find the relevant piece of text in the rules... which is in the description of the Scroll of Dispelling (p.77)*:
If a Wizard or a Dwarf Runesmith has the Scroll of Dispelling he can automatically cause an enemy's spell to fail.So it's a failed spell, rather than a successful one, and thus could be cast again on the same unit with a different spellcaster.
As always, the devil is in the wording. Chris conceded, however, that the way this works is too powerful and should be fixed somehow. Luckily it didn't come up again in our last game.
So, any further thoughts on that from anyone?
* When I checked the rulebook that's currently up for download on the GW resources page, I noticed that the Scroll of Dispelling has the description of the Staff of Spellbinding, with the text from SoD nowhere to be found.