Episode 1:
Challenge Style: Skill 
Time Limit: The time it takes for your patience to run out, or you are found by a muggle
Special rules: If your feet touch the bottom, you fail the challenge 
(not really, but you have to tell us all how)
Richard O'Brien Style tip:
"Teamwork is an advantage here chaps but not essential. The ring on the cache container is NOT UNDER ANY CIRCUMSTANCES to be pulled, it is only there to help it once it has opened. Oh and when your finished, please be a dear and reset the cache's outer container by pushing fully to the right" 
Rules of "The Crystal Maze"
DON'T post pictures of challenge itself (it will ruin the fun)
DON'T put anything other than the cache log back inside outer container (it may not close/open properly)
Be SAFE when retrieving the cache container (especially if it has rained)
DO have fun (being a team will help with this one)
DO be gentle with the container (it wasn't cheap)
DO take note of number on top of log (you'll need it by the end of the series)
Difficulty rating:
For the challenge itself, the stealth required, the likelihood of a person doing this alone is high (not recommended) so hence the high rating.
Terrain rating:
For the location of the cache container, the retrieval and return of the container. And if it has rained recently, this is twice as hard and especially if you are alone!(again not recommended to be alone) 