Being as old as I am and a Londoner to boot I have had years of experience using what is now termed a telescopic whip but we used to call a pole.
Before carbon we had fibreglass poles that had a maximum usable length of seven metres. In the main these poles were telescopic. We used to fish these with a short line, not to hand. The technique for shipping in was to collapse the sections into the butt section until the fish could be swung to hand or netted. Shipping out was the reverse, the sections just pulled from the butt.
This of course meant that on canal towpaths we never had to ship back across the path of walkers and cyclists.
Using this method also means that your 3m rig can be cut down so you have minimal line between tip and float.