Unsanitary Hostel conditions. Seeking advice, what are our rights?

Hi there UK reddit. Were a couple of travelers visiting the UK (London) for a couple of days.

Now our problem is our accommodation. We're currently staying in a hostel that is far from satisfactory. It was cheap so we're not complaining that our room isn't big and dark. But what we are complaining about is the state of the showers. Which are filthy, smells terrible, showers that don't have heat control besides hot or freezing cold. Plus clear and visible mold. Now compared to the advertisements this is day and night. Photos showed clear clean showers. And after checking the other floors those showers seem clean tidy from the advertisements.

Now our question is is what are our rights in this case? The room has already been fully paid in advance. We're quite desperate and we've set to stay here a couple more days. With the hot weather coming in, we want to clean ourselves and not have a ruined trip because of this.

So some advice is greatly appreciated. Much thanks

(Sorry for any errors, currently on mobile)

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