Owl
Draco,
I compiled a list of the different spells Harry may have cast at any place he may be staying, along with a list of the spells that will counter them. I highly doubt there will be any changes, so I expect you'll arrive smoothly.
Good luck,
P.S.: Don't let him off easy. I've also included a list of hexes and spells that I think are rather suitable. My personal favourite is first avis, followed by oppugno.
[Attached is a sheet of parchment, listing all of the different spells along with their counters, as well as a list of spells and hexes.]