Second-hand light goods vehicle

I recently purchased a second-hand light goods vehicle that I will include in my expenses. I will depreciate it over 3 years. Occasionally, I will use it for private purposes. Should I depreciate my light goods vehicle 100% and the costs such as light cargo fuel, maintenance, etc. at 85%, or should I depreciate both at 85%?

I assume that, as a sole proprietor, I can include the light goods vehicle for a full year when I make the purchase in May?

Thanks in advance for the information 🙂