A silenced PCP air-rifle makes VERY little noise - certainly not enough to attract the attentions of "nosey neighbours". (I've an Air Arms s410 with a mod on - barely makes a noise! Works wonders on pigeons and rabbits....and it's .177)
Mess = a health hazard; general licence provisions allow for this. Just make sure no pellets stray over your boundaries - backstop can be as big an issue for air-rifles as it is for centrefires, just the context differs (eg if using in your back garden, don't necessarily think that a fence panel will stop a pellet!)