I think I have an air lock in my kitchen monobloc tap, the water is only coming out at a trickle in the kitchen, but ok in the bathroom. I live in ground floor maisonette so both kitchen and bathroom on same level as tank.
At least one of your cold water taps should be fed directly by mains water. This would normally be the kitchen tap. Some quetions for you. 1. Has the tap that is problematic recently been fitted?
2. Is it just a trickle on both the hot and cold sides?
3. Do the taps on the monobloc open and close by a full turn or only a quarter of a turn?
Have a look at the thread called Mixer Tap not working by AdZc1987 further down the page.