Have read most of the replies to the thread.
I reckon if I were you just pay it.
1 The police may take action because you rode a motor bike on the pavement which as far as I am aware is in itself illegal.
2 What would your attitude be if that was a reserved motor cycle parking bay and a car had been parked in it, bet you would be pissed off.
Just my 2 pence worth.
1- how? Where's the evidence? It's right next to a drop kerb and could very easily be pushed into that position!
On a different note I don't understand the people saying don't fight the council, you won't win- they're not infallible, that's exactly why there is an adjudicator.
Also, putting it bluntly, it's only in london that you legally can't Park on the pavement, it's one of those 'must not' and 'should not' arguments against the highway code, local councils have their own PCN code for parking on the pavement but it isn't enforceable, possibly the warden knows this which is why they used the double yellow code, but being the paperwork dick I am I'd contradict my knowledge against my argument as I enjoy doing that-
feel free to actually research pavement parking! (they are in the process of trying to change it to nationwide but haven't done so yet!)