Have you checked your manual on how to do this?

Failing that:

 

Have you driven the car since adding air? Sounds silly but my vehicles, in the past, have needed to be driven after adding air for the warning light to go out.

 

In the Gen 3, the sensors are wheel-mounted, and have a battery (not replaceable) which is generally good for about ten years or so. They are located on the inside part of the valve stem assembly, so the tire(s) must be removed to change them. They run about $50 or so (US) for a set of 4, but installation is additional. Best to get a sert and have them put in with the next set of new tires when possible. Otherwise, you just have to pay for the installation. Most good shops have a hand-held reader that allows them to work on these. It will detect which one is bad, and is required to reset the system. Most of these shops also carry the sensors, though if you want genuine Honda sensors those are dealer items. You can get them and have the shop install those. THe way the system keeps track of all this data is that each set of sensors contains built-in codes for each wheel. So, a new set will need to be specifically for the correct year model and specs, and the numbers must follow certain sequential sets of numbers. So, if you buy a set of 4, they must be a matched set that has the proper 4-in-sequence numbering. If you replace just one, it will need to match accordingly, so that it does not duplicate an existing ID number or be outside the allowed parameters for the set. Sounds complicated, but the shops know how to do it.

Hope this helps. Moving to Tires section. Welcome to the forum!

 

Pressures for all tires will need to be above 28lbs and then driven above 28mph to reset the TPMS.
Article here:TPMS: Honda CR-V 2007-2013

 

Fill all tires to 28lbs and drive over 28mph to reset TPMS.
Source here:

StackPath

 

I run mine at 30-32 psi, depending on the tires used, nothing lower. Where I live it gets very hot in summer, so in the summertime I usually run them at 30, which will grow when they get hot. In the wintertime I run them at 32, because any lower and they can trip the sensors when it gets cold cold. Today it will be 101F here, so right now I have them at 30.

 

I don't know if the UK TPMS system works the same as US/Canada, so I can't say for sure that what works for us will work on UK models. Post #2 has the procedure to reset it, which does not match what my 2009 EX-L uses for a TPMS system.