Toilet block’s latest leak I repaired - it seems to be the same thing again (9)
I believe the answer is:
lookalike
'it seems to be the same thing again' is the definition.
'toilet block's latest leak i repaired' is the wordplay.
'toilet' becomes 'loo' (loo is a kind of toilet**).
'latest' indicates one should take the final letters.
'repaired' is an anagram indicator.
The last letter of 'block' is 'k'.
'leak'+'i'='leaki'
'leaki' is an anagram of 'alike'.
'loo'+'k'+'alike'='LOOKALIKE'
(Other definitions for lookalike that I've seen before include "Copy" , "Doppelganger" , "twin?" , "Double" .)