Complex sentence: Number Four is a midsized, comfortable and beautifully maintained house (the garden is especially well taken care of) and the Dursleys seem to be a middle class family who lavish all their resources on their son but completely neglect Harry.
Split into simpler sentences: Number Four is a midsized, comfortable and beautifully maintained house. The Dursleys seem to be a middle class family who lavish all their resources on their son but completely neglect Harry.