You've got a couple of decent rods already - what makes you think they won't be perfectly ok? I'm wondering why you seem so unsure. The rivers you mention , plus your saying you fish for roach and dace, point to a match-style rod rather than an Avon, if I can say that without contradicting other posters, as you'll be using lines and weights/feeders at the lighter end of the spectrum.
A match-style feeder rod will be quite capable, with a line of 4lb or so, of getting any Dane chub out, but using an Avon rod to catch mainly smaller species will feel a bit over-gunned and lack fun/feel. You'll probably be catching roach, dace and perch on the Dee, and, imo, unlikely to be using the rather beefier gear that goes with Avons.
There are some feeder rods that would be out of their depth for some river applications. I have the Trent at the bottom of my road these days, and the flow, and species, like barbel and chub, and the size they grow to, mean your average general feeder rod can be inadequate. But for what you describe there's no reason to think you need some specialised "river" feeder.
I looked up your Milo rod, and found a post on FM about something similar from a few years back. Someone obviously likes it!
"If any ones thinking about buying a quality feeder rod then i can strongly recommend the milo helios steve gardener feeder system. For your money you get 4 rods in one. 10' 11' 12' 13' this includes 2 handles and 4 push in carbon tips which have no hint of a flat spot which a lot of feeder rods do have that i have seen.It is a perfect bream/skimmer /roach rod and no doubt would handle carp although i don target carp myself.It has a ultra slim blank.I paid £140 for mine which isnt bad considering you ara getting 4 top end rods for £35 each.The only downside is you can only set up one rod at a time."