The Results are Relative
UKCAT scores are relative to how others do in the test. Your results for each subtest are mapped to a standardised score between 300 and 900.
For example, we’ve had experience of getting the full 900 in a test, despite not answering every question.
It also means that mock tests can only ever suggest what your final score would be. Each year the score boundaries change, and the universities adjust their requirements accordingly.