If no one here claims them, stick them in your computer and look for a text file, most serious photographers will add something on their cards with their name and contact details.
Top Idea Ropes ... I'm off to do that now ... You are not just an interesting user name are you!!
Estelle ... if they were mine ... I'd want them back. Memories are so hard to replace.
Pauljygrant ... see if you can find photo's of a vehicle they were travelling in ... the police might help you track them down that way. MySwaggers always take photo's of their vehicles and campers and applicable rego details.
D4D ... same happened with a card filled with wedding photo's in Ipswich recently. I believe they tracked down the bride and groom through FB (got lots of ideas on how to find them) AND with the co-operation of the local newspaper, who did a front page article for them (I'm told).
Kit_e