Have a look at http://www.sevenseasworldwide.com/ . Their prices seem competative and they deliver door to door. I know of a few people who were satisfied with them and a friend of mine who's moving here next week is using them to ship items very similar to yours. They deliver empty boxes to your home in the UK, collect them when packed and deliver them to your home in Thailand. Delivery takes about eight weeks and they assured my friend ALL costs were covered in the price they quote you, unlike when I had my items (similar to yours) delivered door to port and it cost me another 11000 baht tea money and delivery costs to get them out of the port and to my house 65 km away.
Whoever you use I would always have them delivered 'door to door' and not 'door to port', don't get stung like I did.
absolutely first class company ,would use them any time ,helpfull polite you name it they are the best.
had goods posted to my sister in laws in bangkok as we did not have a house at the time,but for 2000 baht they delivered everything to patters ,the guy unloaded 22 teachest and carried half upstairs ,couldnt recomend them highly enough both in england and thailand.