Very difficult to ask are you on ‘Care in the community’ if yes then you can either follow in * below or contact your advisers office first thing tomorrow.
If you are talking about the inside part of the front door latch housing then it would be cheaper for you to buy a new latch assembly (you don’t need the key barrel leave that in the door) and fit the new one yourself same screw holes on most just take the old one with you when you go to buy one or get someone you trust to get it for you don’t forget to give them the old latch so they get an exact match where possible.
In search box on you computer type in the following
Pictures of Yale lock latch
What comes up shows the inside of the internal latch assembly if its the same replace the spring.
* If not it will work out far cheaper for you to either get someone trustworthy to house mind and go with the old latch to B&Q , Wickes or Homebase or any local hardware store buy a new latch assembly (the key barrel in the door won’t be needed) just the inside latch assembly if its the same as the one in the picture on the search, most screw holes are in same place re-fit the latch assemble ensuring the flat bar on the key barrel slides into the slotted collar on the back of the latch assembly. Tighten screws job done saved around sixty pounds.
bob, February 2013