I have an uberhaus bathroom tap set that seems to be responding differently lately. It take about one second to stop the flow. Do I need to replace the valves?

SOURCE: Having problem with Frigidair PLGF389CCB oven will not lite.

you may need a new gas valve....but i think you should replace the ignitor first. the gasvalve won't open unless the ignitor pulls a certain amp draw to keep it open, since yours is just opening when you hit it, and closing when you hit it again, i believe it is the ignitor

SOURCE: I'm installing a bathroom tap

A coupling will continue the line down as far as you need it.

SOURCE: Getting really hot water to the kitchen but only

If some taps have really hot and others luke warm, then you might have defective mixing valve, check valve, or crossover on single handled faucet.
http://waterheatertimer.org/Crossover.html

Crossover can also cause stacking event. Stacking could be part of puzzle.
http://waterheatertimer.org/Stacking.html

Once crossover or check valve or mixing valve problem is solved, if you have really hot water to some taps, then turn down thermostat to avoid scalding.
http://waterheatertimer.org/How-to-adjust-temperature-on-water-heater.html

Add a comment for more help.

SOURCE: I have a BOSCH 425N

You need to have the flow switch looked at. The low flow of the water to the lavs and the kitchen sink, they all have as small demand next to t bath or shower,
Tom