Hmmm... Perhaps I'm not explaining myself very well. In an ordinary situation, I'd connect the tp link device to the D Link one via WiFi, ostensibly to "extend" the coverage of the WiFi network...

Not sure if this is the best place to ask this, but it seemed the "best fit". We have a WiFi LAN at home, with a D-Link DIR890L as the “root” of that network. I have a large shed – around 20 metres...