I don't know if it's the same worldwide, but in the U.S. hot is left.
Change the faucet, either one will mount on the sink.
One can find out how to install a faucet in a kitchen sink by going to the DIYNetwork website. There is a "How to install a Single-Handle Kitchen Faucet" tutorial by master plumber, Ed Del Grande, explaining the basic steps involved in replacing a kitchen faucet and provides some tips to make the job easier.
If there is a shut off valve under the sink, shut it off and take the line off going to the faucet. Turn the valve on slightly to see if there is water going through it. If there is, the problem has to be in the faucet. Either the washer in the hot water side has come off and is plugging the faucet, or if it is a single handle faucet, the cup is bad. Either one is easy enough to fix. Message me back if you need help fixing it.
Get a faucet handle puller AFTER you remove the screw then follow the directions
There are many places where one can purchase a faucet for a kitchen sink. One of the popular home improvement businesses to purchase a kitchen faucet would be Lowes, they offer personal one on one help with getting the right faucet for the house.
Your hot water line needs more insulation probably. It sounds like your hot water is cooling before reaching that faucet. It may be that the one faucet is not able to turn all the way to hot until you adjust the faucet (usually in the handle) of a 10 year old or newer faucet.
There are many things that one can do with an under sink water heater. The most plausible thing one can do is use it to heat their water so that hot water comes out of the faucet when the correct knob is turned.
First make sure that the hot and cold supply lines (the plumbing) aren't backwards (hot should be on the left as you are facing the faucet) or that someone accidentally ran two hot lines. For the problem to be in the faucet itself you would have to have a single handle faucet. If this is the case the control valve is broken and should be replaced. Three handle Left= Hot Water Flow. Right= Cold Water Flow Center= Controls whether the water comes out the shower head or tub faucet. Two handle Left= Hot Water Flow Right= Cold Water Flow (Diverter Valve is elsewhere if it's a tub/shower) Single handle One handle controls both water pressure and temperature
If the taps and the spout are not connected in one unit, the spacing on your sink is probably 8 inches center to center. The only faucet I have seen for a bathroom sink with that spacing is the two handle type. There may be a single handle available. A kitchen faucet may work if the holes in the sink are large enough. Kitchen faucets are 8 inch also. If yours is 4 inch, then it is no problem, they are common.
There may not be one. You may have to shut the water off where it comes into the house or at the water heater. If there is one under the sink, it should be fairly obvious. Follow the supply line from the faucet.
That would depend on how many holes the sink has .... If it is a one hole type you will need a pull out spray faucet or look at the Delta line
One that will hold the sink, faucet, and let you connect up the plumbing. 24" is normal.