Hi Lobie.
You have to start with the recent info first so previous owner , make contact perhaps look on Facebook if they have pictures have a look through there could be one of them picking up it might offer a clue perhaps a name.
As the bus was from Cornwall try contacting some of the local VW clubs down there somebody might remember it .
If it was around the VW scene then old magazines could be worth a look .
I typed in your DAF reg into google and a number of potential connections came up in images, perhaps a picture of yours lower down although the reg is not clear, also other VW,s with DAF reg numbers , make contact with them a beetle on there perhaps could link you to the dealer who sold them at the time.
It takes time but could be well worth the effort and rewarding for you when discover that little bit of info.
I have recently done it with mine and actually got to chat to a previous owner out in California.
Good luck in your quest in finding your Vamily tree
Cheers Al