Keep, say, eight thousand building blocks in the OXO Tower? (5,5)

'the oxo tower?' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'keep say eight thousand building blocks' is the wordplay.
I cannot quite see how this works, but
'keep' could be 'stock' (I've seen this before) and 'stock' is found in the answer.
'blocks' could be 'cubes' ('cube' can be a synonym of 'block') and 'cubes' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...

'in' is the link.

Can you help me to learn more?