Complex sentence: They have a fierce rivalry with M23 neighbours Brighton & Hove Albion, with whom they have contested the M23 derby 98 times and also enjoy a strong rivalry with fellow South London team Millwall.
Split into simpler sentences: They have a fierce rivalry with M23 neighbours Brighton & Hove Albion, with whom they have contested the M23 derby 98 times. They also enjoy rivalry with fellow South London team Millwall.