The ABRSM offers a number of diplomas beyond the usual grade 8: ABRSM dilpomas FAQ.
Whether these equate to a bachelors degree is another matter. They aren't going to be anything like a music degree, but more of a certificate for advanced level musicians.
You are confusing certain concepts in regards to music qualifications. Let me take the chance to help. In a broader sense there are two types of musical education provided by tertiary institutions in the West. You have conserve training and you have musicology training.
Conserve training was for many years focused on training performers. In England the big ...
Grade 8 is pre-diploma.
Many universities offer a Bachelor of Music degree. There really should be more to a Bachelors or Masters degree than just vocational training, but I believe some colleges dignify their performer courses with such labels.