Hi, there is no need to turn the water off.
The water connection is only for the taps, kitchen sink etc:
Bleeding the radiators creates another problem - you need to turn the water on to restore the pressure, probably to 1.5
Look for a flexible coupling under the boiler.
Last year 64% of the questions asked in our forum were answered within our DIY project pages at www.diydoctor.org.uk/projects.htm The project pages are now separated alphabetically and your answers are accompanied by diagrams and the ability to see, and buy, the tools and/or required to complete your project. Use our search box to look for your answer and save a great deal of time and money!