Your Local Reviewer has been on Holiday for the last 3 weeks
Q1) Can I place caches on the site for during the event then delete them after the event as it will be on a Scout Owned Site. (I have permission from Owner)
You could, but as they would not meet the Longevity part of the Guidelines. They would not be Listed on GC
Cache Permanence
When you report a cache on the Geocaching.com web site, geocachers should (and will) expect the cache to be there for a realistic and extended period of time. Therefore, caches that have the goal to move ("traveling caches"), or temporary caches (caches hidden for less than 3 months or for events) most likely will not be published. If you wish to hide caches for an event, bring printouts to the event and hand them out there.
Q2) If so could I place a cache halfway up a climbing / abseiling tower???
Again due to the Longevity issue it would not be listed on GC. However if it was intended to be permanent, there was permanent access to all (something a Scout Owned Property wont have) and the cache had the permission of the Landowner/Equipment owner then yes.
Q3) When would you publish the event?
As it involves booking accommodation (Pitches) and possibly advanced planning for those attending. Up to 6 months ahead of the date.
However there is one unanswered question. You've stated that it's a Scout Camp, so is the event aimed at just Scouts, or open to all?
If it's just open to Scouts, it would not be accepted for Listing on GC, if the later then yes. Provided there is a element that is Open to Non Campers to Attend the event.
As for terrain, well as there would be no need to camp to attend, and provided there were facilities for the Disabled. It would then be a 1/1
Deceangi Volunteer UK Reviewer Geocaching.com
My post is my personal opinion and as such you do not have my permission to quote me outside of these forums!
Dave
Brenin Tegeingl
Formerly known as Mancunian Pyrocacher on GC