New spot lights help

I have just bought some new spot lights to replace the slightly rusted ones.

Question is do I have to take the whole bumper off or is there anyway I can get my arms in just to unbolt the old ones and put in the new ones? The wiring is all there so it's literally unbolt old and bolt in the new. I was thinking maybe I can just take off the grill or just the undertray?

It's bolted onto the front nothing else.