Odd problem with one of my Beocom 6000 handsets, that I have never seen before. I put a new battery in this Mk1 handset a few weeks ago, but then I didn't use it straight away and it has just been in a drawer.  I came to use it today, and after quite a short while (while I was trying to register it to a base), it just switched off. I figured the battery would be run down so I put it into a pyramid base and left it.  The LED did not flash, and it did not power up when it was put into the charger. After some time had passed, I came back into the room and the LED on the handset was flashing rapidly.  Not the usual flash like you would get for a missed call - it was flashing twice as fast, but the handset was still not powering on.  Then after a while, it made a low beep noise, the LED stopped flashing, and it just stayed off. I wondered if the battery might be faulty so I swapped it for another (I have a couple of new spares), but I still get nothing. I have just lifted it out of the charger and put it back in, the LED started flashing rapidly again, but no power. I lifted it again, put it back in, and it powered up and wanted to be registered to a base, but it didn't last - after a few seconds, it switched off again. Any ideas?