As you are employed with a good income and due to the fact that you have a decent sized deposit i'm confident we can get you accepted on your own for car finance even though you are 18.
The issue is the amount you want. If you had a deposit of say £5000 and you earned over £2500 per month we may stand a chance but from what you've said unfortunately the answer would be a no. With you age and income etc you'd do well to get a maximum of £7000 to £8000 unfortunately. Please apply if this is acceptable and once approved we provide a no obligation quote and you can buy a car from any dealer. Kind Regards, Rachel