An interesting thread.

No owner of a workshop will let fights happen if the workshop / warehouse is still in use, period. Not unless there is an arena containing it all which negates the point of having a battle in that setting. Too much chance for damage / liability. That leaves abandoned or about to be demolished settings. Well generally they are in that state from years of neglect which would make it completely unsafe to have any battles in, which could end up causing more damage to the structures. Not to mention the joys of asbestos.

A better solution would be to dress the arena up in an industrial style and put crates or other obstacles in there. A bit more effort to set up and take down but all very doable. I suspect themed arenas with ideas taken from the original game would be the way to go forward. Chain link fencing around the edge of the arena floor. Floors dress up to look like concrete or tarmac. Stacks of breeze blocks or even old machinery or small cars or rusting motor bikes.