### Clue: Mike's a different bloke after love letter (7)
### Answer: OMICRON 
 ### Explanation: Definition: letter
 [MIC(like "mike", short for "microphone") + RON(name of a bloke different from Mike/Michael) ] **placed below**(after, in a down clue) O(letter representing 0/love in tennis scores).
Defn: … in the Greek alphabet.