Tagged baby starling Medway

We have just moved from a rural area to more urban. We used to have hundreds of birds visiting us but the last six months have been a desert. The bird food was rotting on the feeder all through winter. Not even squirrels would eat it. But, starlings nested in our gutter, and their friends nested in a nearby tree. We now have two families that we can feed and it's a joy to watch. Yesterday we noticed that some of the starlings have leg rings. This morning I noticed that one of the babies (that only emerged from their nest three days ago) is also tagged. The babies from our best aren't tagged. How can I contact someone to tag them, or will they be caught elsewhere? I'm in Medway. I need some more birds in my garden.... :(