Defender prices vary dramatically and are based on condition more than anything else (such as age or mileage). The pick-ups aren't as desirable as the station wagons but the 300TDI engine is popular with enthusiasts for its simplicity. Depending on the condition (particularly how rusty it is), it could be worth anything from around £3000 to £8000. Assuming it's in average condition, it's probably somewhere in the middle.