Mr Boombastic,
When I started, we were 4 non TR and 4 TR. One of the TR applicants was called at a weeks notice (ish) as they had a drop out. I believe this is fairly common so it will depend on your current notice period as to whether you may get a short notice call. If you have no notice period or a very short one give them a call regularly, you may be in luck!
As an aside, two of the TR'd guys were SJ LHS. Both are extremely switched on guys and I for one am looking forward to flying the line with the both of them.