Complex sentence: Tommy has built up a fierce rivalry against Nana Veteran Lionel Seadog over the past few months, mainly because of "The Peckers" constant house warming party invites to all the local treacle which lionel doesn't approve of.
Split into simpler sentences: Tommy has built up a fierce rivalry against Nana Veteran Lionel Seadog over the past few months. Mainly down to "The Peckers" constant house warming party invites to all the local treacle, which Lionel doesn't approve of.