Showing cases spread out over part of plane in consumer guides (7,8)

I believe the answer is:

display cabinets

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

'part of plane in consumer guides' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.

'showing cases spread out' is the wordplay.
'showing' becomes 'display' (synonyms).
'cases spread out' becomes 'cabinets' (I can't justify this - if you can you should believe this answer much more).
'display'+'cabinets'='DISPLAY CABINETS'

'over' acts as a link.

Can you help me to learn more?

I've seen this clue in The Guardian.

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