There's nothing to stop you doing the legwork if you have time. There are plenty of resources out there - try to find similar examples of the vehicles and use their prices as guidance. If you want an independent assessor to come in and help, the Classic Assessments would be worth a call (www.classicassessments.com). Failing that, you could always contact a local auction house as they have plenty of specialists and could also provide you with a route to market if you're looking to offload the cars.