Mac hard drive is showing iOS backup in storage even though I've deleted the files.

Hi, I've created a sym link to have my Mac store my iPad and iPhone backups to an external drive. The things is, having deleted the backup on the Mac hd and emptied the bin, I logged on this morning to find that the Mac is showing that 30GB of space is taken up by 30gb iOS storage. This is in spite of the fact that there is no backup folder in the Mobilesync folder, just the sym link. It did work initially.

I'd be grateful for any help.

Many thanks.