is there a waiting list for combat medical tech

Unfortunately this is not a yes or no answer, as wait times can be effected by several things. Before you start any trade training, all soldiers need to conduct basic training which only start at certain times of the year. As basic training can be filled with nearly all soldier trades, its hard to predict when the next available space will be. This is the same for your trade training. They happen are set times each year. The time of year you apply can also have an effect. They best advice is to apply as soon as you are sure you wish to join the British Army as a Combat Medical Technician. I hope this helps.