Crossword Genius

What sounds like steep part of old England (4)


I believe the answer is:

I'm a little stuck... Click here to teach me more about this clue!

'what sounds like steep' is the definition.
I can't judge whether this defines the answer.

'part of old england' is the wordplay.
'part' becomes 'so' (so is a kind of part).
'of old' becomes 'k' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'england' becomes 'e'.

Can you help me to learn more?

(Another definition for soke that I've seen is "district under particular jurisdiction".)

I've seen this clue in The Telegraph.