Military punishment in attack on King Edward? (4-7)

I believe the answer is:

spud-bashing

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

'military punishment' is the definition.
The definition suggests a singular noun which matches the answer.

'attack on king edward?' is the wordplay.
'attack' becomes 'bashing' (I can't explain this - if you can you should give a lot more credence to this answer).
'on' is a charade indicator (letters next to each other).
'king edward?' becomes 'spud' (I've seen this before).
'bashing' put after 'spud' is 'SPUD-BASHING'.

'in' is the link.

Can you help me to learn more?

I've seen this clue in The Telegraph.

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