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 tell 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 within the answer.
'blocks' could be 'cubes' ('cube' can be a synonym of 'block') and 'cubes' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...

'in' acts as a link.

Can you help me to learn more?