We have three different shipping methods Royal Mail, UPS and UPS before 12.
We want to show Royal Mail up until 20kg, after which it no longer displays and can not be selected as an option.
Another issue is we may want to do this with more couriers, say have Parcel Force up until 2kg.
We have the source code and can make mods, I am just looking for some guidance on the best way to go about this kind of change.
Thanks in advance.