Steve ,get some instilagel or hydrocaine from GP, or pharmacist, it is about £3 a tube/ syringe. It is available without prescription from a pharmasist. It comes in a syringe and is an anesthetic, antiseptic and lubricant, other gels do not have the same properties. The nurses squirt some down the eye of the penis at the side of the catheter. Put a small amount at the eye of the penis and leave for five minutes before inserting the syringe down the end of the penis if required. When I say syringe it is plastic and does not have a needle, just a 3 mm spout.
As an alternative push the penis towards the body to expose more of the Catheter, squirt the gel onto the catheter and let the penis go, DO NOT pull on the catheter.
Make sure the catheter is secure to prevent movement and rubbing. Wearing a pad can make it more comfortable.
Any questions just ask.