First of all depends on their rules.
Most tend to ban high oil pellets these days like Trout pellet and paste, but unless you are specifically told only the 'Fisheries own pellets' are acceptable, then try Halibut pellets and paste-which is actually better than Trout paste.
If groundbait is banned you could cube tiny pieces of meat through a grater and dust them in groundbait, or use liquidised bread or corn steeper via a cup ,with punch or corn on the hook.
In winter caster and chopped worm is deadly on these pools anyway,but as the weather warms up, I think the key is to feed something different or of different size to what you have on the hook.
On venues where maggot brings you only tiny fish, and pellets in all forms are banned, I have used cubes or punched out pellet shaped pieces of flavoured/dusted meat over corn.
You can do that in reverse of course, though wash the fat off the meat first before you riddle it or it can float!
Hope thios gives food for thought but if you let me know what the rules are I will suggest an approach which would work.