Hi John
I have the same problem. Have just acquired a pair of upvc doors and the keys were missing. The lock is not engaged and the doors have been removed from the frame. I have researched the problem. Removing the screwbolt from the edge of the door frees the lock only partially. The key will allow you to turn the barrel 30 degrees left or right and this will move a small locking tab inside the barrel. The barrel then slides out.
Without the keys I have been forced to drill out the lock barrel very carefully. Start with a 2mm bit and progress up to 10mm. I found it easier to drill in the cente at the lowest edge of the key slot. I did break a few bits on the way but I have now cleared one side down to a steel pin in the centre. The barrel is very loose and almost free and with a bit more drilling should slide out very soon. Be careful because when these drill bits snap you could end up with gouges on the frame or your hand/wrist - I removed the lock casing first and this means that any minor slips are covered when this is replaced. On my door the lock sits well below the handle but I guess removing the handle achieves the same.
New barrels are available from ebay quite cheaply but you need the old one to identify the exact size - there are rather a lot. Good luck John.
Dave
Dave Wilson, May 2009
