I can't advise on Q1 - 3, but there are a few scholarship in Malaysia and UK that you can apply for. Chevening and Fullbright and Khazanah Scholarship to name a few. Not sure about bank negara, but its worth looking into.

Personally, I'm sponsored by EPSRC, but that is for Engineering.

Living cost wise, you are looking at around £1400 to live comfortably. about £800 for rent, bills and utilities, another £600 for living expenses, travel, and social activities