Curious to know who does / does not obtain valuations for UK sweet equity?

Hi all - we are often asked to perform valuations of sweet equity in search deals for UK tax purposes: however we're not sure whether this happens in all deals (e.g. where there may be a default presumption that such shares are £nil if under the water at issue).

As such I'm keen to get different perspectives on this from those involved in such deals - who does & does not get such valuations done, and what is the rationale for the decision?