Instead of running a pipe, a good idea is to bend the pipe. The simplest equipment for this job is a bending spring. This is quickly mastered with a little practice. Professionals services such as Brixton Plumbers will use a pipe bender and these are readily available from hire shops. Measuring a length of pipe and marking multiple bends can be a little tricky. Take your time and make one bend at a time. After each one has been carried out, offer the pipe into position and mark the next. If, as is sometimes the case, you simply cant get the pipe into position for marking, you have two options. You can make several shorter pieces of pipe with less bends on each section, and join each length with a straight connection, or carefully mark out the pipe run against the wall and measure each bend, noting of the angle and position before transferring the measurements. A pipe bending spring can also be used. Insert the spring into the pipe so that it spans evenly through the area to be bent. Lubricate with Vaseline if the fit is tight. If its still too tight, make sure youve got the right spring? A spring for the old 1/2″ pipes will simply not fit the metric 15mm equivalent so dont force it. With the spring in place, bend the pipe to the appropriate angle by pulling both ends around your knee. Do so gently though and avoid bending it too far. Even with a spring inside, excessive bending will cause the pipe wall to collapse. Always connect a piece of string to the spring to retrieve it when completed. Dedicated Pipe Benders can make life a lot easier on your knees and are essential when bending pipes larger than 15mm. Professionals such as a Brixton Plumber carry this equipment as standard. Place the pipe in the appropriate size rounded channel. Fit the grooved straight block on the outer edge. Use the lever handles to apply pressure against the straight block. Now continue levering so that it gradually draws the pipe around the circular block, bending the pipe as it goes. Bend to the desired angle then release the handles. Job done.