First of all remember you are both living in this space, so you should be allowed input. On the other hand you can adapt by getting some speakers that are not an affront to the aesthetic. So, do some looking… there are absolutely drop dead gorgeously stand mounted speakers that will look and sound better than those KEFs. Cough up the money.
Also, pick your spot… find one of the locations to be your spot for really enjoying music. Stake your claim.
Also, when you have a plan or Whang to buy something… go all out, wine her, dine her, shower her with gifts.. then bring up what you want to do… how could she refuse such a wonderful guy.
When I was building my audio system my partner (of 37 years now) was into aesthetics of the house and home theater. So I would buy her a really great piece of high end home theater gear… and then buy myself an amp… or speakers… or whatever. Once you treat her first, she will have a hard time denying you.