How do you go about searching English/Welsh records for BMD?

Doing a bit of research for my uncles who comes from Bolton, but have hit a dead end with his English side of the family. The furthest I got is his Grandparents on his fathers side.

Unfortunately he knows nothing about them, how do you track them without dates or places. Have tried the records on this site but have come up empty.

Any help would be welcomed.

Iain