Prove beyond doubt the slab is moving (9)
I believe the answer is:
establish
'prove' is the definition.
(I know that prove is a more specific form of the action establish)
'the slab is moving' is the wordplay.
'moving' indicates an anagram (letters are moved around).
'the'+'slab'+'is'='theslabis'
'theslabis' anagrammed gives 'ESTABLISH'.
'beyond doubt' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for establish that I've seen before include "Found - this sable (anag)" , "Found - institute" , "Set up on permanent basis, or show to be true" , "Show to be true in his stable" , "Found - his stable (anag)" .)