Well M'Lud I might be partaking of a little jaunt along the Rother myself this week, saw somw lovely chub in a favourite spot of mine on Friday, lurking in the slack out of the main flow, which was the speed of an Intercity Express!
Lee is right, the Rother doesn't handle extra water very well, you need to find the slacks!
By the way Sean, the Rother rises in the hills of the Peak District, not exactly "low lying!"
If you want info.let me know, it might get me back into the Port and Stilton good books.