No, the answer is 'ladder'. As you say, the 'L' stands for 'large' while the snake - adder - comes after. My only quibble is that I feel that the clue should have had a question mark after it. Nothing to do with a 'large snake' anyway, cryptic clues are never so literal.
Originally Posted by Flosshilde
By the way, I didn't manage to work it out either!
I started doing cryptic crosswords many years ago after my mother gave me the basic details of how clues are worded. I then went on to compare the clues in the Sun newspaper where the easy and cryptic had the same answer thus enabling me to follow the thought process. I then graduated to the Daily Telegraph completing the Saturday prize crossword every week for years without ever winning the prize. Did the Times crossword for some years but rarely completed it. Nowadays I never do them anymore.
“Every piece of music is a rehearsal of one’s life,” - Sir Colin Davis