So what does all that mean?
I'll try to explain it in sinple terms for you.
Point number 1 means that there are no requirements in the Wiring Regulations for gas appliance supplies to be fused at 3A.
Point number 2 means that there are no requirements in any gas regulations for gas appliance supplies to be fused at 3A.
Point number 3 means that the Wiring Regulations do not make it mandatory to abide by any manufacturer instructions.
Point number 4 means that the Gas Safety (Installation and Use) Regulations (I'm assuming it is they) do make it mandatory to abide by any manufacturer instructions.
Point number 5 means that some gas appliance manufacturers require 3A fusing in the UK.
Point number 6 means that some gas appliance manufacturers do not require 3A fusing outside the UK.
Point number 7 means that nobody knows why #5 is justified, particularly when #6 applies to the same appliance sold elsewhere.
Point number 8 means that notwithstanding #7, #4 means that observing #5 is not optional.
I can't imagine how hard-of-thinking someone would have to be to
truly not understand each of those points.