It is an option to do the ATPL exams straight off, but all you actually get is a frozen ATPL, which means you are unable to exercise the privaleges of said licence until you have 1500 hours. As an extra little kick in the guts if you have not flown ATPL within 36 months of completing the exams the CAA says you have to do them all again! So you have to decide what are the chances of you getting 1500 hours and a twin IR job within three years - none at the moment. Do the 9 exams for the cpl and at least you are on the ladder. At some point in the future when you need to you can go back and do the atpl at leisure and at least you will only have to do it once.