Hi snoz,
The patch panel is for terminating your 15 cables -> RJ45 sockets. You can then label which sockets connecting to which room/outlet (so you don't have to remember which is which)
You will also need patch cables to connect the sockets you want to use to the hub/switch. I don't think 1 cable is enough, as it can only connect 1 socket on the patch panel to 1 port on the hub.
I recently install a 12-port patch panel from Screwfix, whose price I found reasonable (compared to some models I found cheaper on the internet but do not have RJ45 sockets built-in!). Screwfix also does a 18-port version, which might satisfy your requirements. However, those patch panels are for wall mounting, not for professional network racks.
I also bought some 0.5m colour-coded patch cables from Screwfix. Not the cheapest but it was convenient for me because I can just stop by the local store.