Mick, I'd hold out for a little more, the first offer is always a little low. I've had three bikes written off/stolen over the years and I've found that there are ways to come out on top.
The first two bikes to be written off were under valued, however they allowed me to buy em back. I think in the case of my MC28SP they sold it to me as scrap at £500. Mint MC28 were going for £2750 at the time. Like yours it was only bodywork, pipes and loom that were damaged, all of which I had as spares. Anyway they paid me out £2000, minus the £500 buy back, total £1500. I then fixed it using the spares and sold it for £1800. So the total I got was £3200......result!
Similar thing happened with my CBR400, although I sold it to Breakers Yard and made a profit that way.
Of course you might not be able to buy back, but if you can, you might find you can pick it up of peanuts.
Good luck....hope it works out.