Complex sentence: Roy Straitley, the Latin master, and a veteran of St Oswald's, is contemplating retirement, in part because of the encroachment of suits instead of uniform, increased paperwork and use of computers.
Split into simpler sentences: Roy Straitley, the Latin master, and a veteran of St Oswald's, is contemplating retirement. Due to the encrouchment of suits instead of uniform, increased paperwork and use of computers.