split hose - help please

[lockhart flawse]

The long thin water hose from the swirl tank to the bottom of the radiator (?) has split. Can someone tell me if this is the correct part:

http://www.actproducts.co.uk/product/acth030-1m-x-...

For the fitting is it a matter of undoing one end or the other and simply replacing or do I have to do something clever to avoid an airlock? Also the car has lost a bit of water - am I right I thinking I top it up at the the expansion tank?

[lockhart flawse]

Brilliant - thanks a lot!