The BL has a number of Byron’s manuscripts and some early editions of the published Don Juan from the 1820s. Pages from some of them are on-line as image files: well worth exploring.
I have taken the illustration at the head of this post from an 1826 pirated edition (Smeeton) of Canto I that featured plates by Isaac Cruickshank (brother of the better-known George). The image depicts Juan and Julia her maid — the ‘adept’ Antonia — shooing Juan from Julia’s bedroom (he had been hidden in the closet) while her husband, Don Alfonso, searches the rest of the house for her lover.
The verse (No. 182) is Byron at his most suggestive… Julia pleads with Juan who, still love struck, tarries:
“Fly, Juan, fly! for heaven’s sake — not a word —
The door is open — you may yet slip through
The passage you so often have explored —
For comparison, Lynette Yencho’s illustration of the same verse for my audio-iBook of Canto I of Don Juan:
It’s amusing that the British Library notes that the Cruickshank images are “Free from any copyright retrictions”. It was the refusal of the Crown to grant copyright to Cantos 1 & 2 that lead to their widespread piracy by the publisher of this edition (among others).