I want one of these new doorbells (that you plug in to your mains socket). I want one which allows me to use my own sounds. Do you have one?

I'd like to install my own sounds into one but I have no idea what models allow this feature.

Any direct pointers welcomed, especially if you have one of these yourself. What model is it? How much is it? *I'm in the UK, so UK sellers please.

Also, how is the main press-the-button bit powered? Bonus points if it's USB rechargeable and not battery. :) Thanks! :)

For my convenience, please leave the make and model info.

Lastly, it'd be very helpful if item is available on Amazon UK!