Complex sentence: He can occasionally be heard as a continunity announcer on Channel 4, as of July (date) 2011 he announced he was leaving Channel 4 after 10 year possibly to continue narrating on the new Channel 5's revival of Big Brother.
Split into simpler sentences: He can occasionally be heard as a continunity announcer on Channel 4, as of July 2011. He announced he was leaving Channel 4 after 10 years, possibly to continue narrating on the new Channel 5's revival of Big Brother.