They advise not to put on tourniquets nowadays because it leads to loss of limbs. You are not supposed to remove any embedded objects including glass, just gently wrap around with a dressing. Removing the object can cause internal damage and potentially deadly haemorrhage. You are advised not to lift a heavy object such as an item of furniture off a casualty as this can cause further damage (and release of toxic gasses) inside the body. They show you the heimlich but tell you the risk of serious damage too. CPR is allowed and is hard enough but you really need a defib to save a life and who would know where to find one in an emergency. It’s very difficult to navigate the rules beyond ensuring someone is in the right position, isn’t moved, airways free, so they aren’t vomiting, CPR if you can before the professionals arrive.
The rules also change so you have to do a refresh of these courses every few years.