Sorry to hear of your incident, and hope you are on the mend.
Putting the emotive aspect of the machine to one side for a moment, my understanding of what you have said is that you can keep the bike and they will give you roughly £1400.00 (60%).
1)Is the machine in your possession or at a yard somewhere? Just be aware that if it is not with you, cock up’s can occur, and the bike could disappear to a breaker before final settlement, I have seen it happen with cars. - NO, its a company called 4th dimension
2)Get an estimate for you to repair and then evaluate. In the meantime, play hardball on the settlement offered. I will bust it if I have to
The Buell I have ridden for the last 20 odd years was a Harley demonstrator that I bought from a breakers yard and rebuilt, so it can be done, and if you are still passionate about the marque go for it.