Welcome along to Busa Central!
As Cantab suggested, you are better off without it, they can cause more trouble than they are worth, especially the cheapo Chinese ones!
If you have a '99 or '00 model they are not necessary at all as those two models were never timing advance restricted in the first place.
Re the rear seat . . sounds like the cable is disconnected from the latch, I've been there done that too, get a large screw driver and wedge it under the side of the seat and lift the side of it high enough to be able to see the catch, get another long screw driver and push the latch across to free the catch on the base of the seat that's engaged in the latch. It should pop off, mine did. Good luck!
Your bike looks good, no decals and been repainted by the looks, aftermarket rotors too, how many kms? What year model is it?
Post more pics if you can and give us some sorta story about yourself, you know, number of bikes, history etc.
What's your location? Both Cantab and I are in Canterbury.
Enjoy the oRg !