The manuals will list the features but you need to be shown how to convert these features into real benefits. Unless you know what is meant by BLF (Busy Lamp Field), eh "Busy Lamp what? I'm none the wiser" or AA (Auto Attendant), Trunk to Trunk, Hunt Groups, Barge-In, DLI extension, one time DND, camp-on, page zone, live keypads, sequential groups, fax-back, DISA, off-hook voice announce etc, etc etc, how can you possibly know which ones will be money savers, which ones will be time savers, which ones will improve customer service, which ones will increase sales and which ones are no use to your company at all.
You can have a P4L Training Consultant visit your site for as long as required (usually a half day some times a day depending on company size), by the end of which, your whole operation will be noticeably smoother. This may be the best £150 (for a half day) you've spent this month.