lammert - 9:11 am on Sep 17, 2011 (gmt 0)
Hi Mick666, first of all Welcome to WebmasterWorld!
SSH gives shell access to the server from where you can basically access all commands. The first thing the server owner therefore has to do is to create a user account for the admins which doesn't have much priviledges. An account where the base directory is changed to a chrooted directory would be ideal.
From this low-power account, the owner can give access to specific commands by adding lines to the /etc/sudoers file.
Setting this up without creating loopholes requires system level knowledge of Linux.