changed taps and now there's no hot water
Odds seem high that you didn't actually turn the water back on correctly, since the taps in the bath were what you worked on and the kitchen now doesn't get water which cannot be caused by the bath taps - but can be caused by not opening valves after closing them to work on the bath taps. Impossible to provide any more specific hint from afar, but follow the waterlines and recheck all the valves.

I suppose if the new taps were soldered on and you really went overboard with excess solder you might have plugged the pipes, but that's really reaching for a cause (i.e., seems not very likely .vs. just closing a valve you thought you were opening, or the like.)