as others said, keep it - unless it's a lease ? presumably you are doing the miles if it is a disel so phev limited range maybe less interesting,Car finance finishes soon on my Honda Civic i-dtec 1.6 diesel soon, gotta say the car has run faultlessly over the last 4 years no issues at all but questioning whether to go Hybrid or Electric.
honda e-tech phev (like nissan/renault upcoming ones) with more range extender type architecture looks innovative/efficient but well above £20K