In your position with one of those, if the parts are mint, I would strip it and clean everything and eBay it on a "buy it now" on month long listings in pieces. Yes, its a pain pecking out listings and photos etc, but if you save every one you do, and the photos, you can use them over and over again when you buy similar machines.
The fees are 17% in total, but you get postage on top. List them with part numbers in the title and list RRP @ Dyson with a link. For example, the telescopic wand 910415-05 costs £36.23. So its worth an easy £15 + £6 postage. £21. Postage will cost you £4.41 Small Parcel Rate (forget 1st class). 10% eBay fee on the £15 + 40p to list it. 3.4% + 20p Paypal fee on the £21.
Lets do the sums: £21 gross received - minus £4.41 postage; minus 90p Paypal fee; minus £1.90 eBay fee = £13.79. You would be showing an eight quid profit on the machine before you sold the cable rewind, the motor, the hose, the cyclone and any other bits.