LH2 is a good shout for a NF location.
I think you'd need to bump up the budget quite a lot... Greatest Dancer, X factor etc. all have Saturday night prime time BBC One/ITV budgets - and can spread the set design and construction costs, as well as lighting costs, over multiple broadcasts (economies of scale).
The economics of doing something similar for a one-off are very different - particularly in LH2 - which is neither a venue nor a purpose-built TV studio. (Ditto George Lucas 2)
This is why you don't see one-off shows in LH2 or George Lucas 2 - and instead see them in TC1, HQ1 etc., or from existing venues.