It may be hard to find a direct replacement if that filter is 12 years old. Also, Jandy mainly sells through dealers so you may need to contact someone locally or a pool store. I tried to find L250C but came up empty which indicates it may be obsolete. Maybe show a picture of the pipe work because some are side mount piping and others are on top. Where is your backwash valve mounted?
You are correct that it would be best to just undo connections and reconnect a new one but you may have to cut some pipe.
A filter is a standalone item, you do not need a direct replacement by mfg. You could use a Pentair or Hayward or another 3rd party. Look at this website for some ideas.
The decision should be do you want to go back with a sand filter or switch to a cartridge filter. Either is fine. I am guessing that the 250 in the model number refers to a diameter (25 inch) or the weight of sand (250 lbs) to be added. If you go with a sand filter, do not undersize it. What is model and type of pump connected to it.