I also think the doctor & Tylers could be in Cardiff by now, as it's where the rift is. What better place would there be to get messages through to another reality and work on getting through? Owen and Tosh could have been working at Torchwood London so far and come with the Tylers or they worked in Cardiff all along. That's up to you. ;-)
You can talk that through with Tar and Katie as well, if you want.