In the UK, results are often presented as percentages, with a maximum score of 100. In order to help new students better integrate into university life, the results of most majors in the first year of undergraduate studies (Year 1) will not be included in the final undergraduate performance assessment. This means that it is only the performance of Year 2 and Year 3 that really determines your final undergraduate degree. Of these, sophomores usually account for 40% of the overall grade, while juniors account for 60%. 
Honours degrees occupy an important place in the UK education system, including first and second class.
First, second, second and third class honours, active participation in study and research, and continuous improvement of one's overall quality are the only ones who can achieve excellent results at the undergraduate level of British universities. 
Under normal circumstances, if you fail to pass the course and the score is not much, it is recommended to appeal first. If the appeal is really not possible, then consider transferring. Transfer is more suitable for students who encounter problems in their freshman and sophomore years, if they are already in their third and fourth years, and they will have to study for a few years after the transfer, they need to be decided by the new college. From my point of view, I would recommend skipping the undergraduate and applying directly to the master's. You don't have to spend a few years retaking your bachelor's degree, and your undergraduate degree always comes with the risk of failing again.