Plumber

oldagetraveller1

"Viva Skylo" - Nowt wrong with those. Installed them myself, and I'm ancient too, in two toilets in the house. Easy to change, like for like, if they do fail. Easy to adjust both short and full flush.

Guess what they replaced, which both failed - yes, Thomas Dudley syphons.

sonearandyetsofa

You should pay for the work that you contracted them to do, once they've finished it. If you brought the guy in to repair your leaky cistern, and allowed him to go ahead and fit the parts he'd brought with him, then the issue here isn't the parts he fitted - it's the fact that the work isn't finished, because it still leaks. You had the chance to say "That's not what I wanted" before he started the work. You already knew at that point that he'd brought a full kit. Regardless of whether you believe him when he says that it had to be the full kit, you definitely knew that's what he planned to fit when he came to you. 

What exactly do you want from the guy? Do you want him to fix the leak? That sounds like a reasonable outcome, given that's what you're paying him for. Do you want a formal apology and him to agree with you that he lied about the products he sells only coming as a kit? I don't think you'll get that, you can't force him to do that, and attempting to insist on it is not going to help matters when it comes to the leak.

If I took my car to the garage and said "I want this XYZ model tyre fitted", and then when I brought the car in some guy came over with an exhaust and told me he was going to fit that as well, I would tell him not to go ahead with the work and I'd take my car somewhere else.

born_again

I would say they fit full kits, as they get fed up of fitting bits & then getting called back as another part broke & they are getting the blame for that.