Hardy lass has time for a bit of mosaic work (7)
I believe the answer is:
tessera
'bit of mosaic work' is the definition.
'tessera' can be an answer for 'bit' (I have seen 'Bit of design' mean 'tessera' so perhaps 'bit' could also mean 'tessera'). I'm not sure about the 'of mosaic work' bit.
'hardy lass has time' is the wordplay.
'hardy lass' becomes 'tess' (in Tess of the d'Urbervilles, Thomas Hardy novel).
'has' says to put letters next to each other.
'time' becomes 'era' (an era is a period of time).
'tess'+'era'='TESSERA'
'for a' acts as a link.
Can you help me to learn more?
(Other definitions for tessera that I've seen before include "Mosaic component" , "Reseats (anag) -- small tile used in a mosaic" , "small bit of artwork" , "Small mosaic piece" , "Small stone for mosaics" .)