Normal
I have never seen a firm stipulate a candidate needing first class grades or even a first class overall degree average. The highest I have seen as a requirement is a high 2:1 (68%) average (Cleary Gottlieb). I think a few firms like Jones Day and Slaughter and May ask for a strong 2:1 (65%+). Most firms look for a 2:1 so would expect that would be the condition for retaining the TC, as is passing the LLM SQE (1 & 2).