Welcome to the team......
if you are in kms you are not UK, so give us some clues where you live.
the choke slipping is answered above, so you should have that fixed by the time you read this
sounds like you have the big tank [19l] if you are talking about "fuel bars", as the digi fuel gauge cme in with the new tank.
if you need to calibrate the safe distance, take a fuel can strapped to the pillion and ride till it runs out, then you know exactly how far you can go after the last bar.
I get 100miles to the red light on my 16l tank, and it will then take about 12l to fill, so if it did hold 16l, it would have a range of 130miles .
one other trick is to fill the tank with the bike fully upright [sit on the bike when you are filling it up] , not on the side stand, then you get more in.........its not a big tank, so you have to get it nice and full.