Just got off the phone with Dennis. Apparently he is allright. Ribs are really sore but not actually cracked, he reckons. He is sore but no problem riding the bike. He is in a hotel on the anatolian side of Istanbul.
We sorted the tires. Found the dealer who had them in stock (thankfully). He now has the address, the phone number and the GPS coordinates of the tire dealer. Also has my mobile number in case he needs any further help. The place is actually quite near to his hotel so the whole thing should be finished in a couple of hours. I'll call him back in a couple of hours and see if its all good. Will keep you posted here.