Through the offices of Canon William Nelson at Canterbury cathedral (later Earl Nelson), brother to Admiral Horatio Nelson, a small shield was erected high in the north vault of the nave around 1808. To the original family arms of a black cross on a shield of gold, were added three 'augmentations' (additions permitted by the monarch for some particularly meritorious act) - the three exploding bombs for victory at Copenhagen, the extravagant riverside scene for victory at the battle of the Nile, and the wavy text of Trafalgar for that victory. General heraldic opinion is that this degree of augmentation, obliterating as it does the original shield design, produces an unfortunate dog's breakfast.
What to see (binoculars would assist!) all in Image 1:
the small shield of Lord Nelson very high in the second bay from the west in the north vault of the nave
the partially rigged man of war (top left hand side)
the unimpressive stab at a palm tree (top middle) stood by the River Nile
the three bombs depicting victory at Copenhagen
Sources: Canterbury Cathedral Chronicle 2006