Negotiating estate agent fees

So we have a housemate moving out and a couple coming into the flat. Our estate agent are asking for three charges of £110 to cover the checks and admin. I'm sure you'd agree that this is unreasonable, particularly when I know that we all paid £50 on entering the contract.

Does anyone have any advice on how to approach the agents/with what tone to lower the price? I'm sure this problem doesn't just apply to me so any professional or other knowledge would be much appreciated.

In the London subreddit as it seems to more an issue down here.