I assume they are quarter turn ceramic cartridges. You will need to either identify the manufacturer and get the right ones from them; or take one of the cartridges AND the handle to a Merchants to see if they have the right ones.
There are so many variations on these that just 'any old one' will not do. This is why IMO it is better to buy a branded tap so that spares are easier to source.
If it drips from the spout, then one of the quarter turn cartridges/valves is passing. Probably best to ring the manufacturer and ask for a replacement set of cartridges for the tap. (The hot and cold cartridges will be different, so unless you can isolate either hot or cold to be sure which one is the problem. You should order both)
If you can get the cartridge out, count the number of splines on the cartridge end e.g. 18-20 or 20-24, it helps to remove it because they are two sizes/ measurements in the overall length and by getting it out you then know you that you can remove it, easier said than done with some taps
Go to Lunns website ( Hampshire I think) click on cartridges, and look down the list of cartridges for the number of spline you counted
They list the measurement for the cartridges displayed( over 100 different ones in the section I was searching for but a distinctive red e clip made it easier) usually two sizes to help you locate the right cartridge
This is not a cheap process especially for 3/4 or bath size taps
You may be left feeling that a replacement set of taps would be cheaper
Good luck with it
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