Primitive accommodation English hoover up (4)

I believe the answer is:
cave
'primitive accommodation' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'english hoover up' is the wordplay.
'english' becomes 'E' (abbreviation as in OED).
'hoover' becomes 'vac' (I am not sure about this - if you are sure you should believe this answer much more).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'e'+'vac'='evac'
'evac' in reverse letter order is 'CAVE'.
Can you help me to learn more?
(Other definitions for cave that I've seen before include "Natural underground chamber" , "Hollow in a rock" , "Hollow - warning" , "Primitive dwelling" , "Watch out" .)
