A small nut and bolt. Use a blunt drill bit (I seem to have lots of those) to drill the plastic, with hign RPM
but slow progress, so it is really melting the hole rather than drilling and cracking. Then finish off with the adhesive
of your choice, 5200 being a reasonable possibility. Then the load is off the adhesive
If that option does not appeal to you, sand or drill holes in the plastic where the latch will be mounted, so the adhesive you choose has more surface to grip.