To get back to the OP's actual question.
Fall arrest anchors have to be very securely fixed to the structure of the building or be very heavy as they need to resist the dynamic load of a falling human body. I doubt very much that a DIY version at a reasonable price is available.
Fall arrest anchors have to be very securely fixed to the structure of the building or be very heavy as they need to resist the dynamic load of a falling human body. I doubt very much that a DIY version at a reasonable price is available.