All sorted after presenting the older users (the more difficult ones) with the options. Hands-down winner was - I hate to say - Google Gmail/Calendar for email and calendaring. They particularly liked that they could enter appointments in a logical way such as "Meet with Mary 11.30am" and the calendar would take care of entering the appointment accurately into their default calendar. My only concern is the way Google tend to close-down services at near-zero notice, or worse still integrate them with Google+ and default all the data to "absolutely publicly available"

But I have a balancing act of reliable/manageable IT and managing user expectations - if they like it, they use it, etc.
File sharing duties are still a choice of SME8 or a simple NAS appliance, like the QNAP devices. I like that I can backup a QNAP to an external drive and still have access to the files direct from that drive in the event of server meltdown. But that's more what makes me happy rather than them, as accessing a share for them is the same either way.