So, Laguna Beach Utila, yes?
Do not assume that they have rental lights unless they specifically advise you of the type and number.
A nice place to go, but you're pretty much so at the "last stop on the line".
The Bay Islands have excellent night dive possibilities. Time to buy a light and bring it along if you want to night dive more than once... anywhere. It makes economic sense.
Batteries there are prolly $1 each.
Remember, the difference between "primary" and "backup" is a velcro pocket.
I dive many times with two UK 4C lights. You really don't need a big light as a primary.