Specific fic (BBC version)

[ryokoyuy]

I seem to remember it was part of a series, but it may not be. It was definitely John/Sherlock.

The scene I remember is John leaving after a fight to go to Harry's (? I think) and Sherlock thought he was gone for good, even though he didn't, as John pointed out later, take anything more than his keys with him.

There's a scene where they meet up in a park to hash this all out.

Ring any bells?