Blocked Cold Water Taps In Bathroom

Hi, I'm looking for some help and advice.

I have a shower mixer tap connected to my bath and several weeks ago it stopped converting back from water through the showerhead to water through the taps. So now I only get either hot or cold water from the bath through the shower mixer's hose regardless of how many times I push or pull the shower/tap converter fitting on the tap. I've been able to live with this since I have an electric shower as well.

Over the past couple of days the cold water from the basin in the bathroom had started to run with less pressure and this morning the cold water has stopped completely from this tap. The hot water from basin is still OK though and all other water supplies are OK i.e. downstairs sink, washing machine, toilet, heating. I'm assuming the problem has occurred due to an air lock of some sort from my cold water supply.

Any sugesstions on how to unblock this would be appreciated.

Not an air lock.

could try dismantling the tap ?

OK, now I know the basin problem and the shower mixer problem are not related. I've managed to sort the basin problem out. The small inner spring had came loose under the handle fitting. I'm still no better off with the shower mixer though. I take it if it's not an air lock problem then it's got to be that the up/down switching valve is knackered and is stuck in the shower position ?

try the same methodoligy