Safety device earthed badly — struggle to get into it (4,9)

I believe the answer is:

head restraint

'safety device' is the definition.
(headrest in a vehicle)

'earthed badly struggle to get into it' is the wordplay.
'badly' indicates anagramming the letters.
'struggle' becomes 'strain' (I've seen this before).
'to get into it' indicates putting letters inside.
'earthed' with letters rearranged gives 'headret'.
'headret' placed around 'strain' is 'HEAD RESTRAINT'.

(Another definition for head restraint that I've seen is " Protection against whiplash".)

I've seen this clue in The Guardian.

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