i have bought several rings from turkey and have always used
marmaris gold centre, the service is top rate and they will make any ring to your spec, we bought our first ring 4yrs ago then had it altered last year( more stones added) when i bought myself a ring.
free shuttle to and from maramris normally your apartments can arrange this do have a card for the guy who we see every time but cant seem to find it, will pm you if i manage to find it.
its worth a visit just to see the £30,000 plus items on show.