I feel Nest has not done their research for the UK market with the power requirements for this is not he norm in the UK for doorbell chimes and transformers. Nests own community site/forum has a long list of people trying to figure out how to get this to work. Most doorbells in the UK are 8V or maybe 12V but Nest requires a 16V Chime and transformer. You may be able to find a 16V chime but trying to find a 16V transformer is very hard to get hold of. Alternatively you can use a 24V transformer but then it’s near impossible to find a chime that takes 24V. So this is not a good first impression of the product.