There's plenty of spare capacity outside the peak morning and evening periods. Night restrictions would have a very small impact on passenger increase as the majority of extra movements would occur during daytime. Achieving 35mpa does require larger aircraft mix, eg Gatwick, but the fact that the 25mpa cap and movement limit has been increased means the schedulers have more flexibility in slot allocation and passenger numbers to what they have presently. It doesn't necessarily mean that the 35mpa figure will be reached but it ensures best use of the single runway and terminal. The terminal and aircraft parking areas would need some more development though as passenger and aircraft movements increase.