Hello. As someone who has received offers for this year, I would definitely recommend getting further experience. Social Work can be an incredibly demanding career and increasingly challenging! Therefor, universities definitely favour those who have a large amount of experience and extensive knowledge for the career. However, its not impossible to get onto a course without having as much experience as someone else may have. I know people who have gained offers straight from A Levels. However, this could have been down to them having relevant personal experiences or unique insight to the career/course.
Also, speaking as someone who has also undertaken the BTEC Extended Diploma in H&SC, I really feel like this course doesn't provide you with the skills and qualities needed to get accepted and to commit to such a challenging course that Social work is. I took a year out and am now doing an Access course and can't even explain how much more you learn and how well it really does prepare you for university. I'm not just talking experience but also written skills, strong academic assignments, working to very strict deadlines, learning and understanding