Regarding the lowside...i think that dukes do crash fairly well, and lowsides are usually just cosmetic damage. If the bikes been fixed via the insurance claim then, as he says it 'should' be OK...but he should also be in posession of all of the receipt/paperwork for this.
If the bike hasn't been ridden for two years then, yes, it does need a service. Even though it has not done the mileage, the belts will need changing as they can become problematic if left unmoved for prolonged periods of time. It would also be worthwhile having it seviced anyhow for other parts such as fuel/air/oil filters, all fluids etc.
Your looking at perhaps £200-£250 for a good (equivalent to a 6k mile) service, obviously depending on were you take it. A point worth rembering when haggling on the price
[Edited on 1-9-2004 by Harv748]