This year's Henley Forum Annual Conference (it's the 19th!) takes place 06 - 07 March 2019 at Henley Business School Amplifying our practice: leading the way with knowledge.
I usually attend this conference every year and will be there again this year. To my mind, it is the best KM conference by far, both in terms of speakers, content and interactivity. The location on the banks of the river Thames is also hard to beat.
You don't need to be a member of the forum to attend. If you are interested in joining contact Marina Hart - her details are on the webpage linked to above.
If you are not familiar with the Henley Forum and the amazing research work that they do - go take a look at their Knowledge in Action Leaflets - 38 x three or four page downloadable reports on a wide range of topics from "Improving conversations to enable effective knowledge sharing" to "Embedding change".