Yes, Annie singing in a bar and introducing the Seth character was done very quickly, but it's a great story, and one that develops the Annie character significantly.
It was nice to see Caroline and Richard working together on a story line, especially one that wasn't centred on their 'will they/won't they?' romance.
The Charlie/Del story was a bit more throw away, but still had its moments.
On the whole a vast improvement in quality in this episode.