OP, I don't know how old your dd is - what is 1st yr GCSE - 14? I think it really depends on the sensitivity of the child and their maturity. I think my ds is very sensitive and it would severly traumatise him. Mind you, he is only 11 still. We live in Germany, quite close to Dachau so he will be taken with the school, as every Germany child has to visit a concentration camp.
I would deem this trip for your dd non-essential, and I wouldn't feel pressured into feeling you ought to send her.
Is there a jewish museum somewhere near where you live? I bet that would adequately summarise the information. Visiting one for real obviously gives such a real perspective of the sheer daunting size and scale. I visited Mauthausen concentration camp in Austria when I was 16. It left a deep impression on me, but I don't think this would necessarily be necessary for school work.
I would like to say one thing though -
The vast majority of the holocaust weren't jewish though. There were approximately 11 million holocaust victims in total, 6 million were jewish, so a majority figure, and certainly the single largest group, but 5 million victims were not jewish, millions of Poles, Soviets, Romani, homosexual, handicapped, political, many who hadn't done anything 'wrong' at all, but they looked funny at someone or pissed off their neighbour.
I don't see it as a rivalry, more as a need for recognition and understanding that so many people, I think Poles being the 2nd largest group, suffered so terribly.