Hi Murv
Can't agree regarding the avon rod for a 20lb carp... in fact, I think an inexperienced angler has got a better chance of losing a 20lb carp on a 3lb tc rod through hook pull. The lighter rod will bend a whole lot more, which ultimately gives you a bigger margin for error in a last dash for freedom under the rod top.
I'm only stating a personal preference here - but I find the whole experience much more fun with a proper bend in the rod. Ideally, when I'm landing the fish it should be going through 90 degrees from handle to tip.
I've caught several in that kind of size bracket on a 1.25lb tc rod with no problems at all. In fact, I've often found that pound for pound, a lower double will often fight much harder than an upper double or twenty (which tend to plod around a bit)
What this rod won't do is fish long range - or fish heavy flood water. I'm in full agreement that you need to step up then.