Ford KA brakes and heating

sounds like you have a air lock in the water system run the car up to temp and turn the fan on to full and the interior switch on to screen this will release any trapped air in the system if this doeant work then you have a blockage now on to the brakes remove the wheel and properly look at both inner pads and outer pads dont think that because the outer pad has lots of material left doesnt mean that the inner pad will be the same what you will find is the inner pad will be worn out lower than the pad on th outside off the caliper also feel the disc if there is a lip / step on the outer faces of the disc then this will also want replacing but they are not expensive but do note when you go to order if you have solid discs or vented as they always ask

Most fords use a heater tap on the bulk head, these often go faulty and are easy to replace, as for your brakes, can you pump the pedal and get a better response on the second application of the brakes, if so it is a matter of stripping the rear brakes and manualy adjusting them as with so many auto adjusting brakes they don't work. At the same time check the wheel cylinders for leaks

your brake pads will be seized in and for your heater it will require a new heater valve that lives under the bonnet on the bulk head