i have drained the water tank in the loft through the hot water taps but the copper boiler seems still to be full
If there are any holes or places of access on the boiler I suggest you use a siphon to drain the tank. Use a garden hose. Fill the hose with water, put a sprayer on the end of the hose and turn it off so the water cant drain out of the hose. Stick the other end of the hose into the tank, get it all the way to the bottom. Walk the capped end of the hose down the stairs and outside. Take the sprayer off the end off the hose. Gravity will cause the hose to drain and instead of having to suck on the hose the water that you initially filled the hose with will do the work for you. This will drain most of the water out of your boiler quite quickly.
How about drilling a quarter-inch hole in the very bottom and draining it completely from there. Then thread it and insert the proper plug. You could also put in a small saddle valve if the physical configuration will accommodate it.
