Original sentence: When she was first elected to parliament in 1997 she joined her twin sister, Angela Eagle, who had been elected at the previous parliament, to serve as probably the first set of twins in the House of Commons, but certainly the first set of female twins
Edited sentence: Another set of twins, Sylvia Heal and Ann Keen, had both been elected at the 1997 election, also, meaning that neither set of twins holds the record for being the first set of twins.When she was first elected to parliament in 1997 she joined her twin sister, Angela Eagle, who had been elected at the previous parliament, to serve as one of the first set of twins in the House of Commons