You will need to apply with a Level 3 qualification in addition to meeting their GCSE requirements. This means you will need to do A Levels, BTEC or an Access course in addition to GCSEs, for example. If you have further questions about admissions you should direct them to the UCLAN admissions team.
What do you mean by "worth it?"
If you mean is it worth completing these qualifications in order to be a vet, then yes.