Flexible pipe with stopcock.

[Juman islam]

Okay. The water regulations apply whether it is an installation to last a century or to last a minute. Glad we've cleared that up.

So buy a Hoselock check valve hose connector to connect to the tap. (After the check valve, materials do not have to be suitable for drinking water, which is why most garden hoses are not WRAS approved). Get a garden hose and connect to the connector, and then put a spray gun or similar on the other end. And hope thay can withstand hot water. Done.

Something like this I imagine?

Hozelock 2181 Non Return Valve 688970679398 | eBay