I am in the middle of week 9, nearly there, but pretty much every run as soon as i start i need to go the toilet, for reason or the other and sometimes both. A couple of times i have made sure that i had pre-run bathroom visits even when not necessary and it has seemed better.
Maybe it is my mind trying to stop me from starting a thirty minute run. My first 28 minute run had me really strongly needing to go at the start, but i wasnt stopping once i had started.
While it may be acceptable for a paula radcliffe style stop while out doing the london marathon, it would not be appreciated on the treadmill at the gym.