Although we can't provide a valuation for a specific car, we can give you guide. Mini projects of this era are still around for under a grand (just), while an MoT'd example that needs work would fetch about £2500. We'd expect to see the very best example on a dealer's forecourt for about £5000. To maximise the value of your car, you should really get it re-commissioned and MoT'd. But I appreciate this could be a bigger job than you're willing to face - if it's been in storage then you'll need to make sure the brakes are working, replace the tyres (which are over ten years old), replace all the fluids and service items, and deal with any issues that may have been caused by fuel left in the tank (blockages in the tank) and make sure the cooling system is in good condition... and any other issues that drop up. Low-mileage cars can be desirable - but low-mileage cars that haven't moved in a decade come with problems of their own and potential buyers will use these to chip money off the price. That said, any Mini that is bodily sound is worth good money.