I'm trying to follow the tutorial from this website but I have been unable to get any further than the "More things to do with objects" as I cannot find the Ask/Tell Tab.

I have looked in the "Features" tab but the only options I get are Use/Give, Container, Switchable, Edible and Player.

Am I missing something obvious?? I am currently using version 5.6.3 of Quest on Windows

It is the Features tab of the game object, rather than the specific item.

with more versions, more and more GUI/Editor Tabs have been added, cluttering up the GUI/Editor, so now they're by default toggled off (hidden), so you got to go and toggle them back on to see/use them, and Pixie has already told where to do this, here's the link on the changes with quest over its versions:

http://docs.textadventures.co.uk/quest/upgrade_notes.html

and if you want, check the links to the blogs (within the above link) as they talk more about some of the features that have been added