Unsure whether to sell car to clear debts

Hi all, looking for advice on my situation not my previous decisions please.

I’m 22 y/o and have around £3.5k in credit card debt at the minute, and own my car worth ~£21/22k outright. I’m still living at home, for the next few years until I have enough to move out and rent/buy. It’s not the cheapest on fuel being a 2 litre and also potentially going travelling next year for 3-6 months and going into the military so will be doing a lot of driving. Is the best option for me to sell my car and buy cheaper using the rest to clear my debt? Was thinking of using £10k or so for a new car, clearing my debt and sticking the rest in an ISA. (I have student loans etc but not including those for now).

Many thanks