Value of 80s/90s Scalextric sets

Hello! Hopefully, I am allowed to ask this here... I wanted to check if there are any resources for identifying the value of some classic Scalextric sets? My family is moving to another country and we are therefore selling most possessions that have been stored in our attic for many years.

We came across two sets from the 80s/90s: Mighty Metro and Porsche Turbo (C583) and have already had several people approach us to purchase them, which made me think they must be worth something, but I have no idea of their value (if indeed they have any value at all). I have tried to do some basic searches online but didn't really come up with anything useful, so I'm not sure where to turn now.

Any help you can give would be greatly appreciated! Thanks!