Dont take it to a gunshop haden 1 - they have (allegedly an obligation to "conviscate" it, though that may depend on how well they know you, or how they see you as a shooter.

Get yourself a combro if you suspect it's close to or over the limit. google "combro" This has been refered to because you have stated it's doing12 pounds. If you live on that permission, I personally would'nt worry too much about it, but if you have to travel to it then potentially you risk losing it and a fine if the only concern is one of power.

control rabbits anytime you or the landowner wants

And welcome to the forum. Most replies to questions will be factual, but there are always a few who like to selectivly read and twist things around a tad, or become alarmist - especially if you didnt follow the rules about filling in your profile.