Dreadfully disables the securely settled (11)

I believe the answer is:

established

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'securely settled' is the definition.
'established' can be an answer for 'settled' (similar in meaning). I am not certain of the 'securely' bit.

'dreadfully disables the' is the wordplay.
'dreadfully' indicates anagramming the letters (a dreadful spelling).
'disables'+'the'='disablesthe'
'disablesthe' with letters rearranged gives 'ESTABLISHED'.

Can you help me to learn more?

(Other definitions for established that I've seen before include "just like the church!" , "Settled and recognised" , "He is baldest (anag.)" , "Set up; settled" , "Long-standing" .)

I've seen this clue in The Telegraph.

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