Spa article – longing to get stuck into that (6)
I believe the answer is:
aachen
'spa article longing to get stuck into that' is the definition.
'aachen' can be an answer for 'spa' (I've seen this before). I'm unsure of the rest of the definition.
'spa article longing to get' is the wordplay.
'spa article' becomes 'an' (I can't explain this - if you can you should give a lot more credence to this answer).
'longing' becomes 'ache' (longing can mean aching or pining for something).
'to get' is an insertion indicator.
'an' placed around 'ache' is 'AACHEN'.
Can you help me to learn more?
(Other definitions for aachen that I've seen before include "German spa city" , "old European city" , "spa town" , "Whither good news was brought" , "German name for Aix-la-Chapelle" .)