Hi, we were recently given a set of two underwater pond lights with transformer. (The mains part with transformer is plugged in in the conservatory). Unfortunately, the cable from the transformer to the lights is about a meter too short for where we want to place the lights. But oddly, it is co-axial. (We have only met this in TV type-things before). Can we make a joint in the cable, using a length of TV co-axial and joiners? We have seen YouTube videos on how to do this. The plan is not to put the joins under water, but in a protected box, under decking, with only the original cables in the water. We do not want to tamper with the cable entry to the lights themselves as this is well sealed. Advice would be much appreciated. Thank you.