I am not aware of any professionally trained Leica tech repair experts in Singapore. However, Philip Tay is a good bet, he has been trained by Hasselblad and Rollei, and he has some Leica's himself and services them.
The nearest Leica techs would appear to be in Hong Kong. Mr Lee of Panda is one you can check out. He did a good job for my 90 TE. I went to his shop in Stanley St and it certainly gives a lot of comfort.