Go for whichever one you like most, those numbers don't mean anything if you have differing levels of interest. Someone with a 1st/2.1 in MechEng who has taken part in Formula student, etc, etc is a far more attractive candidate than someone on a 2.2 in EEE with no extracurriculars.
In addition, Electric cars and Renewable energy are both still largely mechanical engineering dominated. For AI, you won't really have gone into depth enough with a bog standard EEE degree to get a career out of it.
There's also really not that much difference in job prospects between the two, using the crude "graduate prospects" measurement from CUG, the top 20 for this have an average score of about 90 in EEE and 89 in MechEng.