Firstly the facia of the stove will need to be removed, this can be done by removing the bolts of the facia these are the bolts that look slightly gold there is one above the door leaver arm.
Once these have been removed you will be able to remove the whole catch assembly, I have attached some pictures on a step by step of how to do this.
If you place your knee and the bottom of the door and then push down slightly on the top of the bracket if the pin was there you would then be able to slide this out and then,
this will then compress spring and allow you to then be able to take the spring off and then slide the whole unit down.
If you then do this in reverse you will then be able to place the pin back in, there is no tool in order to do this. The facia would then be able to be bolted back onto the stove once this has been done.
There are step by step pictures below of the process.