Home DIY

How can I shore up a wonky sash lock?

The mechanism inside is knackered somehow, and I need to pull it out of the door to have a look inside it.

But, the chippy that I got to put it in (which, in hindsight, I really should have done myself), has bodged it with a load of filler.

What's the best way to put it back? I was thinking either:

• fill the whole thing up with filler & cut out the space again; or
  
• cut a chunk of pine / whatever wood I have sitting around to fit, then fill the gaps with filler, and then cut the space again; or
  
• build up the sides of the hole (with 2 part filler), so that I can cut a better fitting hole for the lock body without having to hog out as much material as 1 or 2.
  
• fill it out with packers