You can get special fixings.
Also depends on what type of blocks you have.
Do you have Aircrete blocks such as Celcon or do you have hard blocks.
( if you can knock a large nail in to it fairly easy you have soft blocks)
Screwfix will have some for hard blocks.
But for the softer aircrete blocks you need some special large plastic screw looking plugs.
You drill your wall screw these large plugs in then screw your bolt screw into that.
I got mine from a company in Lincoln called Fixfirm.
You should find a similar company near you.