Complex sentence: On 23 February 2013 Humphries lost Liberal pre-selection to one of his successors as ACT Liberal Leader, Zed Seselja, amidst much controversy, in particular over party members, including many prominent ones, being barred from voting.
Split into simpler sentences: On 23 February 2013 Humphries lost Liberal pre-selection to one of his successors as ACT Liberal Leader, Zed Seselja. This happened with much controversy, in particular over party members, including many prominent ones, being barred from voting.