Hi Jessica,
A somehow related question. As a law graduate from a university in the EU, I was wondering if adding percentages would help in this case. At my uni to get a first somebody has to be in the top 5% of the class (we were about 400 students per year). Does a first also mean top 5-10% of the class in the UK? I was in the top 20% and got an upper 2.1 (UK equivalent). I usually add this percentage, but I am not sure if it helps or makes my grades look worse.
Indicatively, Oxbridge accepts students from my uni with a high 2.1 so I assume they are somehow aware of this (but perhaps GR teams are not?).