Ssh – Locked theself out of Amazon EC2 SSH – This service allows sftp connections only

Doh.

Locked myself out of SSH on an Amazon EC2 box after fiddling with
ForceCommand internal-sftp in /etc/ssh/sshd_config in order to allow root log-in via SFTP.

SFTP still works fine, but PuTTY dies instantly, e.g:

The odd thing here is that SFTP still works fine and permits me to log-in as root currently (because of the changes I made) – so I've got a WinSCP window open and I can trawl through whatever I like and edit stuff.

When I try to connect from another Linux box using:

ssh -i keyfile.pem ec2-user@hostname.com.au -p [portnumber]

I get the following response:

This service allows sftp connections only.
Connection to [hostname] closed.

I've successfully removed ForceCommand internal-sftp from /etc/ssh/sshd_config but I'm having trouble running service ssh restart remotely. When I do it from sftp with the ! prefix, it says it's worked – but I can tell that it hasn't because the listening port is not changing.