Hello @2BB
Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about stone benchtops.
I'm sorry but none of the stone tops at the store are rated for outside use. Technically you can install it outside, but it will void the warranty of the stone top. Outside also refers to a covered patio or shaded pergola. If it is outside your house, it is out of warranty.
For a low-cost alternative, I propose using SpecRite 2200 x 600 x 26mm Multi-Use Merbau Panel. It is rated for outdoor use and if sealed properly will provide a long service life. The best part of course is that should any burn marks or accidental damage happen the timber top can be sanded back down and resealed like new.
If you need further assistance, please let us know.
Eric
