Gold Coast Models - Need advise

I sell some HO items on eBay and came across a very unusual set of 4 model kits at an auction. I'm sure I paid too much for the 4 kits, but had never heard of them before + I loved the wooden boxes in which they were sold. I put them on eBay with a high price, not knowing what to expect. They are from 1971 as far as I know and the last picture shows an ad for the items. Gold Coast Models 73' & 83' HO Kit Freelance Pass Cars Wood - Any information about the company or the kits would be appreciated. And if you have any idea about a realistic value, please suggest.
https://www.ebay.com/itm/392448549618