Gerard,
Unless I’m missing something, I’m not sure you are ready for a plyometric program. I checked the math, and if you’re times are right and your top speed is 18kmph then as you are saying it would take you close to 20 seconds to cover 100m at full speed. In a 100m dash, you’re probably looking at 22-23 seconds. At your height, weight and age, there is something going on…either incorrect measurements, incorrect calculations, or you are in very poor condition. If it is the later, whether as a result of a medical condition or simply being really out of shape, you should first work to build up your general physical condition by going through several cycles of a low impact GPP. Weights, acceleration work, hills (both long and short) and a lot of slower extensive tempo for several weeks before I would attempt any type of ballistic or plyometric training. Your acceleration and speed will improve dramatically without the plyos.
If I am missing something, I apologize, but those numbers just don’t jive with your stats, at least for a reasonably conditioned individual.