Cat D (or whatever it’s called now - CAT N) isn’t really a bad mark for a car of this age. Most cars over 10yrs old that have an accident are “written off”
You just have to remember that the term written off isn’t a mechanical statement but a financial statement.
So weigh up all 3 options
1. They repair it all back to factory
2. They give you the money to repair it yourself
3. They write it off and they give you £
Clearly 1 is the best option but most costly
3 isn’t a bad issue as they may pay you £2k and you buy it back for £500
Keep your mind and options open
You are lucky with this car as all the panels can’t be painted off the car which makes the paint guy happy and you are a mechanic with access to tools
should be a doddle
As for the headlamp washers - I still think a normal panel will work
JJ