So the humbrol enamel will dissolve the plastic bottle
No
the material doesn't allow hobby paint to adhered to it
Yes.
Bottles are usually polythene, which is pretty robust with regard to solvents, but for much the same chemical reason also pretty immune to having anything stick to it.
So the humbrol enamel will dissolve the plastic bottle, my main plan is to sand the area a little roughly and then paint it.