I have been fishing Medway at Yalding quite a bit last season but only couple of times the canal. I had one small perch out of the canal.
River provided couple of jacks, some tiny perch and abundance of minnows. There supposed to be some carp up to 20lb i have seen many carp hunters coming with all the gear but not once heard of them actually being caught. To be honest its not very interesting fishing over there but it is the only river I can get to in under an hour.
I have always seen guys fishing the canal just by the canoe point on the right side of small bridge leading to a pub. Once someone told me there should be some bigger perch and chub around the marina that is under the bridge as you come to Yalding from the side where train station is
Good luck! I might pop in there sometime soon myself