Hi Dave,
Have a look at the website for Pla restaurant from the K hotel. It is at Surin Beach. I see from their website that they have extended and improved their outdoor area since I was there last October. I'm sure that they would set you up at a table on the beach for dinner as they appear to have these tables set up in the day time. You could ask for it to be away from the other diners, most of whom will probably sit in the main area just back from the sand. It is a beautiful spot and very romantic with the candle and lamp light. Great food from Pla and also have a look at the website for the Beach Club run by the Twin Palms Resort, also at Surin Beach. Where are you staying ? It's so nice to see a man wanting to be so romantic and thoughtful, most don't bother. The flowers are really cheap in Thailand, why don't you arrange an enormous bunch to be sent to the restaurant and present them to her during the night. Another idea is to arrange some flying lamps for you to let go into the sky from the beach. Have a look on Youtube under flying lamps Thailand. The Pla restaurant is owned by the same man who owns K Hotel in Patong, maybe you could call in to see him and make the arrangements with him. I think he is Austrian and he speaks perfect English. To find K Hotel walk down Bangla Road away from the beach and when you get to the end, turn left and it will be a minute or so walk further down on the left. You will enter through the garden area. if the owner is not there ask for Robert, the head Chef. Sorry I can't help with the jewellery. Have a look at Cathy & Gary's web pages, they may have some information on jewellery.
Regards
Michelle