I've read that I should be doing a final protective wash prior to winter commencing, but my car can become very dirty very quickly due to living in the countryside. Any advice?

We need to get a good coat or 2 of wax on yours and mine Steph and then it will be fine to jus jet wash it down once a week

weekly, get that salt straight off!!!

I try for weekly, but when you had feb-march this year it was 8 weeks that i didn't wash my car.

Was still in a top condition after though

buy some finish kare 1000p and put a couple of coats on the car, that will see you right through to spring.
then just wash weekly or so with a lsp safe car shampoo, and use a quick detailer afterwards.

hardly ever clean my car in winter i dont see the point when its white, i drive half a mile and it looks the same again