Hi Juliej My oh has to do this test also, last year at 39 she wouldn't have to take it, now she's 40.... lose 5 points due to age...
she feels the same as you. I have tried to lessen the insult to her English heritage by stating it's not to prove she's English, it's to gain an extra 5 points via the 'back door' to achieve 120 points, small comfort I know, I don't have to sit it, I'd still be cheesed off. For what it's worth my advice would be to sit it, read the threads on this site with regard the choice of 175 v's the 176 visa routes.
Good luck with your decision.
Paul.