The day, kneeslider, will come like it did with me on my first DT300i (RIP). Old guys take longer to get in position than to unlatch! Turn bars to right, get on ground in front on machine right, look up at back of ign. switch, grab cable housing on bottom of switch and pull to machine left. A few yanks should pop the seat open.
Do what it takes to lube the whole cable assembly NOW before every inch gets wet and rusty. I must follow my own advice!
Karl