Good learning opportunities
In general conferences and conventions are organised on a county or national basis, sometimes with the addition of workshops and/or demonstrations. It is expected the standard of presentation will be high, but that may not always be the case. On many occasions I have been disappointed by the presentations of well known speakers, where very often it is those who are seen as lesser speakers that I have enjoyed listening to far more. They are often practical beekeepers who are speaking from their own experience, not effectively reading from a book. I strongly suggest that you do a bit of research before booking to avoid possible disappointment.
Single lectures are usually confined to evening meetings, but they will probably be the same ones that are part of a conference or convention.
I list below some of the well known and regular events, although I haven't attended them all. I have linked to them, so you can see the latest information at source.
Gormanston Summer School... , Organised annually by FIBKA over 6 days... I attend this regularly. There are two simultaneous lectures, with additional workshops and a beginners programme. This is a great place to see beekeepers from other parts.
BIBBA... Organise various different events and workshops... The biennial conference is held in even years. This is suitable for all beekeepers, with high quality presentations.
BBKA Spring Convention with Lectures and trade stands.
The National Honey Show... Three days. Honey Show, Lectures for beginners and advanced, workshops and trade stands.
Central Association of Beekeepers... Autumn Conference, Spring Meeting. Scientific lectures.
Scottish Beekeepers Association... One day Conference. I have never attended.
Welsh Beekeepers Association... One day Conference. I have never attended.
Apimondia... A worldwide event held over 6 days... every biennially (odd years)... a different country each time. I have never attended.
There are many more than those few I list above. There may be other events that may be suitable for your requirements.