Complex sentence: Glyndebourne booked the LPO instead of the RPO from 1964 onwards; and the RPO was excluded from the London Orchestral Concert Board's schedule of concerts, which meant that it was denied the use of London's main concert venue, the Royal Festival Hall.
Split into simpler sentences: Glyndebourne booked the LPO instead of the RPO from 1964 onwards. The RPO was also excluded from the London Orchestral Concert Board's schedule of concerts, which meant that it was denied the use of London's main concert venue, the Royal Festival Hall.