Now that I have served my probation,

, I have linked below a pic of of the bike, which I put a deposit on yesterday.
The current owner pointed out to me one problem with the bike, and its out of character with everthing else about the bike, Its the seat, or rather the seat frame, When the seat is lifted the underside is very badly rusted, to the point that one of the clips/hinges is loose. The current owner is at a loss to explain, apparently its been like it since he acquired the bike 4 years ago. (discount negotiated)
Anyone ever seen anything like this type of corrosion on a seat frame?, the rest of the frame, and other parts on the bike, are, I would say in above average condition, for the age, with little sign of corrosion anywhere. The bike has been stored inside, and only occasioally used in the last 4 years, which is believable, due to the size of the vintage collection it was stored with.
The edges of the body coloured painted tail/seat cowling piece is also showing rust, Its a pity as the seat upholstery is perfect , I may have no option but to replace the seat. A new one available on Motobins ( sans tail piece), but looks rather plain/smooth without ribbing.
First job though will be an oil/filter service, I must order the service kit now from Motobins. Thanks to Monte for forwarding the pdf manual, Its great the way the manuals of older bikes actually give instrustions on routine servicing to a fair level of detail! I'm assuming I need the 79/80 service kit, 81 up looks like it has a more modern square air filter.
In order of priority what other service items should I tackle?, Due to lack of use, the current owner has admitted only one oil service in last 4 years, though carbs were balanced, brake lines replaced, and battery replaced (the latter only yesterday).
Possibly I have posted all of these initial questions in the wrong place, sorry got carried away with my "to do" list,

