We came to know of this place through our cab driver and were we glad he did! We checked in the day before we were to fly out of Colombo back home. The place is tucked away in a narrow lane behind Carnival Ice cream. Once you enter, you feel as if you were home. Our room was in the basement and it was one large room- there were 2 large beds, a TV, modem with wi-fi, a huge bathroom with the works! there was also a kettle to make your own cup of tea or coffee in the room. There were 3 lights, an AC that kept us happy in the warm summer day. 
The room we stayed in is called “Banyan Den”

The front, near the entrance

Our room
 
The bathroom
 Elaborate breakfast they served us the morning we flew out

Upon mentioning we were vegetarians, John & his wife served up a feast for us- each of the dishes were divine and we ate away greedily! The room was priced at $60 dollars including breakfast and for dinner they charged $5 only. The couple were warm, caring and made our stay a memorable one. The place is about 20mins from Galle Face beach and is on the main road, so there is easy access to banks, stores, restaurants and everything else you could desire! 
I highly recco this place to anyone travelling to Colombo, Sri lanka!
Address:
# 263/6 Galle Rd, Colombo 9, 
Sri Lanka
[In the lane behind Carnival Ice cream] 
Ph: +94 11 2 301672
Website: http://www.colombohaven.com/