Sorry about the delay replying to this - been a bit busy at work! Thanks for all the comments. Replies to some of them below.
I haven't had a barbel on the maggot feeder if I'm fishing it at the top of the swim with the pellet at the bottom. I don't really know why this is and it may well just be that the chub feed more aggressively in the cold water.
I agree with Eric that it may well be worth fishing just one rod in these conditions. I fish the chub rod to give me some action (and maybe a big chub!) as I've not got a lot of patience. If I was fishing just one rod I'd fish a maggot feeder.
No Mick isn't related to Ron Beecroft.
It's sad that I'm not going to have the chance to give it another go for a few weeks. The banks of the Swale are too dangerous in these conditions and, as John says, the amount of salt going into the rivers when we get a thaw will kill it for a week.