Glad it all worked out ok for you - that's the first thing I'd say ...
Sweeping is essential, especially if you have lots of nooks and crannies in the chimney. Maybe think about having it done more often to make sure it gets everything out.
I tend to have a number of Corvids typically throw things down my chimney, seeing if anything sticks - if they get one right, more will follow as they'll be thinking about a nest site. I have a block built chimney, almost all straight up, and a good 400mm square (quite hard to get going some nights, as that's a lot of space to heat up) - but when I sweep it out I get almost nothing, as it all lands on the hearth behind the register plate, having no where to catch things.
If your birds do the same, and your chimney is hooky, something'll stick sooner or later.
In my experience, having a well maintained wood burner, and a decently fitting register plate will help control a fire too, as you can shut out the air rushing into the chimney from below.
Lining is an option, but it'll affect your fires draw (and not always in a good way), and more often than not it's quite a big job. Have a word with your local sweep, a good one will know his chimneys well, and can advise from there.
Good luck.