1. Cop shop, they can deal with anyone who comes along saying they've dropped their life savings / money they took out to put a deposit on a flat / other essential large wad of cash and all the business of trying to prove it. I'm not rich, I have some debts to pay off, and it'd be nice to get £1280 with no strings attached (it's a touch over my monthly take-home pay) but I can cover it without falling below the breadline. I have more than that locked up in long-term savings accounts that I can get at if I really need to. For all I know that may just as likely be all the money the person who lost it had in the entire world, ringfenced for something in particular, as much as it might be the proceeds of a drug deal gone wrong etc.
2. If it sits around long enough to become mine, then... pay off remaining credit card bill, have things fixed on car and bike, put remainder towards this year's holidays. I'm a simple man with simple needs and rather thin safety margins.
3. Anything left over out of THAT will be shoved immediately towards my mortgage lender as one of my allowed overpayments, as I haven't made any of those which I'd originally planned to thus far...
... or alternatively, I have been promising myself a new laptop for about two whole years now, and it's starting to get a bit critical. The old one needs to be pensioned off for an easy life as a glorified NAS before too much longer.
Might go buy a week's shopping made up entirely of branded goods without a single yellow- or red-stickered clearance item in the entire basket, too. Maybe a full-price DVD, even.
Woo, so exciting, go me. But you try living your life on eighteen grand a year as a singleton and see how quickly your expectations and standards slip.
No particular charity contributions mentioned as one thing I haven't backed off on is the things I already make regular (or as-and-when, depending what they are) donations to. Though there is one I'm more directly (albeit still rather loosely) involved with which has had a patch of trouble and needs a particular broken piece of equipment replaced - I figure it could be easily dealt with by a moderate fraction of this windfall.