Pigeon nest in an awkward place

Hi all,I need a bit of advice on what to do about a pigeon nest that I've found 

I work at an agricultural machinery dealership and we have a combine harvester in the yard that needs to be moved (sadly this is unavoidable) but I've discovered a nest on top of the engine

What's the best thing I can do leave them be and hope for the best or try and relocate it 

There appears to still be an adult tending to the nest,any advice gratefully received