A few things that need sorting!
1. The problem of boarding and disembarking international flights at the same time, what a shambles.
2. Aircraft calling for push when they are not ready.
3. Aircraft taxying for departure too early for their slot and other aircraft having to wait for take off.
4. Crews having to clear customs when there are no customs in attendance.
5. Can ATC have the full departure clearance available prior to start, not having to wait for the squawk on taxy?
6. How about a dedicated clearance frequency at busy times?
ABZ ATC are second to none by the way! I know you must be undermanned and under resourced.