My mate Simon asked me to sort these vehicles out for him and turn them from toy cars into wargame models. I've put together model kits before but these were the first "classic car" models I've dealt with.
The brief was to retain the original colour and markings and so I washed them, weathered them with dry brushing, and flattened the colours with Matt varnish. I also repainted the radiators and painted mud splashes on the sills. I think they turned out OK, hope you like them.
The bottom photo shows the original finish.