If your son changes his mind about having yours Stevie, I might be interested. Decided to get a winter hack myself, and would prefer a Fazer 6, but it'd need to be pretty ratty looking, fairly high mileage, to keep the price down. Don't think somehow yours would fit that description anyway!
It's a pity the old Z650s are fetching silly money these days, much more nimble than a Zephyr 750. Still a good bike after all these years.