Hi Edward
many people have found the information given here very useful:
http://www.thetortoisehouse.com/Hibernation04.htm
If you decide to hibernate the tortoise I suggest you read that and also
this one has good info:
http://www.tortoise-protection-group.org.uk/site/35.asp
As you say there is conflicting advice. In the end we all have to make a personal decision for the tortoise in question. It is important to check that the tortoise is in good health and a suitable weight to be hibernated.
Some of us think it is beneficial but many do not see an advantage for the tortoise in being hibernated and there may be risk involved. The risk can be greatly reduced by planning and careful management. In some cases sheds can get too warm when the sun shines on them even in winter.
If you decide to hibernate the tortoise, there will be a load of people on here having similar concerns and asking the same questions that will occur to you.