Some reflections on this job having now done it... If you're thinking of replacing your Panda 4x4 rear trailing arm bushes, first have a lie down and see if the desire goes away. If not, or it is really necessary, I hope the following is helpful.
Point 1, I wonder now if the Sealey wind-out tool (referenced above) was discontinued because it may have been completely ineffective in practice. These bushes are not designed to be replaced and the whole job is pretty time consuming and needs some more serious tools. If you try and wind a bush out you will simply pull out the rubber centre - the metal outer sleeve is steel and a very tight press fit and (I have found) has to be hacksawed in two places and then hammered out with a drift to remove.
Be prepared for the bush through-bolts to be rusted up, if the bushes are worn and have let water in. Sheared bolts will need patient sawing of the remains.
The new bushes really have to be pressed in - they need about 2-3T force to drive them fully home. This means removing the whole arm from the car and probably removing the rear hub carrier complete with brake disc (depending on how much space you have in your press). Seized brake pipe connections will likely be an issue on any 15+ year old 169 4x4, but a cut to the top of the retaining brackets and temporarily bending out a section means you can lift out the brake lines complete. Remember to loosen the driveshaft hub nuts before you start dismantling.
Having refitted the arms to their pivots, the springs need to be compressed into quite a restricted space, so choice of spring compressor(s) is critical. I have a single-screw, broad yoke type which worked OK.
Be sure to place the driveshaft within the hub (or space where the hub would be if hub carrier has been removed) before fixing the arm to the chassis otherwise you will have to drop and move the diff to get enough room to replace the driveshafts....(how do I know that...well...)