Complex sentence: Kate went to an all girls school, and had a horse called "Treacle" it is therefore assumed that she was relatively well off-however she feels she doesn't get the attention she craves from her mother.
Split into simpler sentences: Kate went to an all girls school, and had a horse called "Treacle". It is therefore assumed that she was relatively well off; however, she feels she doesn't get the attention she craves from her mother.