I am pretty sure you need to take the bucket under he seat to get to it. 
Things to note on these models. They use metal HT caps.. Change it for a NGK or similar. 
The valves tighten up on these and a lot of times this is the issue when it wont start. If you a near Milton Keynes I know a very good mechanic who will get it going for you...
                
 bb
                
 February 2011