SonyEricsson T707 was dropped into water. On recovery (2mins ) later stripped outer covers off and removed battery and sim card. Used hairdryer on unit for about 20mins. Can you suggest anything else I can do before re-assembling the unit and switching it back on?

The next thing to do if you drop your cell phone in water is to remove the battery immediately without even hesitating to turn off the power. This reduces the risk of a short circuit which would render your phone useless. Dry the batter with a towel and set aside to dry thoroughly. The battery itself may or may not work again, but fortunately batteries can be replaced fairly inexpensively. Even if the battery does work, it is a good idea to get a new one so as not to risk it leaking battery acid in the future.
After you have removed the battery, dry off the cell phone with an absorbent towel as best as you can. Use cotton swabs to soak up water in crevices and on any fragile, exposed circuits. If you have dropped your cell phone in water, it is also helpful to disassemble it if you can and let all the parts dry separately. Just be sure that you know how to put it back together. If it is a flip or sliding cell phone, leave it open for maximum evaporation.
If you drop your cell phone in water that isn’t pure such as a beverage or in salt water, rinse the phone off with fresh water once you have removed the battery. Once you drop the phone in water, the additional rinsing will not do further damage, however, minerals or other materials will.
If you drop your cell phone in liquid that isn’t pure water, you may want to try giving it an alcohol bath. The alcohol will displace minerals and microscopic substances as well as aiding in the evaporation of the fluid. If it is available, you should use an alcohol concentration of 95% rather than rubbing alcohol that usually contains only 70%.
Once your phone is clean, leave it in a warm dry area or near an air conditioner for three days before you attempt to replace the battery and turn it on. This is very important, because although you may think that you have thoroughly dried it, the slightest moisture can react with the battery and cause it to short circuit. If drop your cell phone in water, and want to save it, resist the temptation of turning it on to see if it is working until you have waited at least 72 hours. Unless you have insurance for your cell phone which covers water damage, there is no point in sending it to the manufacture with the hope that they will replace it under warranty. If you drop your cell phone in water, the technicians will be able to tell immediately due to moisture sensitive stickers that are contained inside almost all cell phones. The best thing to do is to try the tips mentioned above and repair it yourself.