Credit Utilization

Apologies if this has come up before, I've searched the forum for credit utilization but nothing has answered my query.

I am currently obsessing over my credit file (not the score but the finer details that affect eligibility) and am trying to calculate my credit utilization. Currently;

CC - Balance - 3k Limit 6k
Next Directory - Balance £500 Limit 6k

Puts my utilization around 30% between these two accounts. I also have an overdraft which I have never used, it was from my student days and is set at £1750 but like I said, I have never used it.

What I wanted to know was, I also have a PCP car contract which shows a balance of around 15k currently. However, this account doesn't have a credit limit in the sense that I couldn't borrow more or reduce said limit.

Does this impact upon overall credit utilization?

Thanks