It depends what you mean by unrepresentative. If you are saying this because of 78 - I do not agree. Generally a sample of 30+ is adequate to infer a normal distribution. If you are referring to unrepresentative just because it is from one specific school for instance or geographical region, then yeah - maybe.

I disagree about the rest of the test being easy. I think yes, LG was easier than usual (though the London-Madrid was still not too easy), but I found the LR to be the hardest part.

RC was I think also of average - to above average difficulty. I think LG was the only section that maybe was easier than usual.