Doorbell transformer

I would hire an electrician to safely isolate and disconnect the supply to the transformer then you could remove the rest of the installation yourself. This should only take a Short amount of time and you should only be charged a minimum of a hour slot.

You really should get an electrician in to remove the cable from your fuse board. Only professional electricians should ever take the cover off and work on these. You can however turn off the circuit at the board that controls the bell ( usually a lighting circuit), take off the cover of the transformer that covers the cable that goes to the bell ( usually very thin, white cable, 2 core ) and remove them from the transformer, then replace the cover and turn on the circuit. That 2 core cable now does nothing.

No I would get somebody in to remove the supply to the transformer as this is 240v , from the transformer to the doorbell will be a very low voltage. Better safe than sorry.

I strongly advise you contact a electrician to fully disconnect your doorbell. As the transformer feed is supplied from your fuse board and only a qualified electrician should work on this. But if you find the fuse which supplies the doorbell circuit you could turn this off, and then remove the low voltage cable coming out of the transformer which goes off to your doorbell. Once this is removed and the Transformer cover fully replaced you can switch the fuse back on as this might be doing a lighting circuit as well.

Get an electrician to disconnect the transformer from the fuse board, then you can safely remove the wiring and transformer

There is no job in a consumer unit that is within the scope of even the best DIY’er. Best call a professional, a little job like that would be a small fee under £100. Why would someone risk it.