outside tap in my shed but meter upstairs in the kitchen

Once your meter it is in your kitchen any connection downstream will no be read by meter ( illegal) If you want outside tap you need to run a pipe after your meter which is in your kitchen to outside tap..

Hi, this seems like an AI-generated statement which answer your question. You cannot install a tap using someone else’s property supply without their agreement, even if you own the downstairs property, as each unit typically has its own supply & agreements. The legal and ethical questions therefore should rule out using the neighbours supply. The best option is to run a pipe from your kitchen, outside, and down to the shed using copper (above ground) or MDPE pipe (cannot be exposed to UV sunlight therefore use UV protected trunking and insulation). using MDPE could mean buying a single coil of pipe this pipe will run without any cuts from the kitchen to the shed. The MDPE cannot be laid over the ground, you'll need to bury it 750mm down this is UK law and prevents freezing, accident punctures and the weight regular garden use. This is deeper if there's car parking over it. Include an isolation valve for winter and maintenance, and a double check valve before the pipe exits the kitchen.

Hi Any extra water supplies needed; connection have to be after the water meter. Any connection you do before the meter is not permitted.

If there is an existing facility as long as you can determine who's property runs it and they are happy to have it reinstated then it wouldn't be an issue