Flexible tap connectors are not always simple to connect to pipes, as they often come with a ½ BSP male or female threaded end, people often connect these directly to a 15mm compression fitting or a 15mm isolation valve, but now there are much better options, such as flexible tap tail connectors or flatfaced isolation valves. This video shows how to use flexi tap tail connectors or flatfaced isolation valves.

You can see some videos where I have recently used flexi tap tail adaptors and flatfaced isolation valves here
   • How to change a tap in a vanity unit  
   • How to change a kitchen tap   

Links to the products are here

Flat faced isolation valves on BES https://www.bes.co.uk/flatfacedstra...
Amazon https://fave.co/2UV1NZj
Ebay https://fave.co/2Ng9k3I