This is a close call between conservation and restoration. The real clue lies in the fact the there is an inaugural function that brings to close a project that kept the headquarters in scaffolding. The fact is that we normally do not have a specific project for conservation that runs for a time period. Conservation is an ongoing thing. We only have restoration projects that aim at renovating worn out things. So restoration is better suited in the context. Here the word ‘retained’ has been given to mislead the audience to think that retaining should relate more to conservation than to restoration. Nope! The retaining pertains to the headquarters in scaffolding and not to conservation.

Restoration is my choice