This puzzle was distributed by Elgar at the S&B 8 meeting on 24th May 2011 and he has kindly given permission for it to be reproduced here. Although targeted at those attending, the notes below are still helpful in solving the puzzle, as is the post announcing the meeting.
Start with A in the Northwest corner and Z in the Southeast corner.
Having discarded the A-Z, entry of T and L confirms your (S&B) attendance in the Crow’s Nest (clue 5) at the Ship & Shovell (diagonal), address 1-3 (clue 1), (clue 16ac) (clue 24). From 4 heading toward 30, follow the instructions in clue 9 under the 12.
[For those unaware of the identity of the "absent friend" please see this post on Derek Harrison's Crossword Message Board.]
15d contains a special character in the unchecked square
16d is not in Chambers, the Oxford Dictionary of English or even the New Oxford American Dictionary.