Thanks Selden, looks like quality stuff. Unfortunately, I might have to take it to a dealer for a carb clean as I've rather shamefully never had to learn to do anything other than the most basic maintenance tasks on bikes. I'd like to learn but not having a garage and having to keep the bike in a cramped space outside my flat doesn't help.
Bike has a fresh spark plug, oil and filters. Have got it booked in for a valve clearance check in a couple of weeks time, they've probably never been checked in twenty years.
Probably for a separate thread but some other issues I'm having with it are difficulty on occasions getting it into first from neutral at a stop. I understand this is fairly typical though and a bit of revving, rocking back and forward or movement of the clutch usually works.
Also, I have to set the idle speed very low to barely there and gently nurse it to stability for about ten minutes on starting or else it races when the bike is properly warmed up. I'm assuming this is a carb issue and understand from my reading on this forum that there are various mods you can do to make it less cold blooded.
Overall, really enjoying the bike though. I'm basically using it as a more fun and occasional off road replacement to the Yamaha Xmax 125 cc scooter I had previously. Seems to be getting almost as good MPG as the Xmax too.