A steep approach (5-6 deg) should qualify for a reduced threshold crossing height (35 ft), which in turn gives an increased LDA from the geometry.
Duck under – well don’t try that from the ‘city end’ at London City Airport as the bridge and road lights get very close even with a 1:29 OFS.
How do you ever know that you have missed all of the obstacles? A typical human assumption that often precedes errors and accidents; don’t duck under / land before the threshold.