Complex sentence: However, this decision was later amended to exclude four battalions and after a successful campaign by the Royal Irish Fusiliers (Princess Victoria's) it was agreed that the disbandment would not be of the most junior regiment but of the two most junior battalions.
Split into simpler sentences: However, this decision was later amended to exclude four battalions. After a successful campaign by the Royal Irish Fusiliers (Princess Victoria's), it was agreed that the disbandment would not be of the most junior regiment, but of the two most junior battalions.