Given the No. 1 carriage? (4)
I believe the answer is:
shay
'carriage?' is the definition.
(I've seen this in another clue)
'given the no 1' is the wordplay.
I cannot quite see how this works, but
'1' could be 'a' (both can mean one) and 'a' is present in the answer.
The remaining letters 'shy' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for shay that I've seen before include "Little Seamus" , "carriage" .)