I think what you are after are wear patches for your tubes? They can be obtained from a number of tube makers such as Henshaws in Somerset. However since you are in Essex you could also try Inflatable Boat Supplies in South Woodham or a company called SEMS Aerosafe in Basildon. SEMS do repairs to tubes, liferafts etc and have done work for me in the past and are good value. The wear patches stick onto your tubes. I think its a reasonably straightforward job to DIY.
Out of the fog......