Cheers guys, some excellent feedback from you both, much appreciated
Just so I don't get confused

this is what I envisage...so how would you guys go about setting it up?
I will have two structures - the Sirius Observatory with all the imaging gear inside and nearby (4m) will be a separate fully wired (power points and lights) and fuse boxed industrial site shed (not connected to mains) as a control/warm room, I will also have a 3.5kva generator/inverter that can provide up to 2500W (2200W continuous) of pure sine wave 240V AC power.
I would like to setup the generator system to be able to power both the shed and the Observatory but have a mechanism in place to allow me to refuel the generator safely without interrupting the imaging.
Can I do this and if so how might I approach it?
Thanks heaps for the input
Mike