Gives up office for cats and dogs raised on top of Sperrins in Northern Ireland (5,4)

'gives up office for cats and dogs raised' is the definition.
I can't tell whether this definition defines the answer.

'top of sperrins in northern ireland' is the wordplay.
'top of' suggests taking the first letters.
'in' is an insertion indicator.
'northern ireland' becomes 'stepdown' (I can't justify this - if you can you should give a lot more credence to this answer).
The initial letter of 'sperrins' is 's'.
's' inserted into 'stepdown' is 'STEPS DOWN'.

'on' acts as a link.

Can you help me to learn more?