For what it is worth, I would keep the K for fun and buy a cheap R1150GS, put an Adventure tank on it (mine had one), ride it like you stole it and fill up once a week.
It will keep up with most bikes on a commute that involves traffic, will cost nothing to run, Tesco's services them while you wait (it is called filling up) and you will sell it for the same as you bought it for if you ever sell it!
If it ever goes wrong, which it won't, the girl in the local chippy can fix it with nothing more than a fish slice and a dollop of chip oil!
Brian (who says ride high, ride fast, ride dry, and ride cheap
)