Good luck with the search, warning though, ownership is addictive
You are probably are looking hard enough. The issue is that they just don't really exist new and people that do have any are not going to let them readily go or advertise they have stashed away in the back of the garage
3 probable routes for replacements
Very, very occasionally they turn up on the evilbay etc, but expect to pay $$$$
Post a WTB add on 914World - you may get lucky
People here regularly break cars and cut panels
That said on the whole wings stay fairly solid and you will be surprised what can be salvaged. For areas that commonly rot (around the door handle recess etc) Restoration Design make repair panels
Good luck & let everyone know how you get on