The most common and most likely answer to this crossword clue is the 6 plus 8 letter word ALBERT MEMORIAL
I've seen this crossword clue in The Sunday Telegraph
A
L
B
E
R
T
M
E
M
O
R
I
A
L
More clues leading to the result ALBERT MEMORIAL
Buddy explains!
The straight part
We know that "London monument honouring German, close to Victoria" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case london monument honouring german, close to victoria = albert memorial.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.