Is lone working illegal?
No — but under the Management of Health and Safety at Work Regulations you have to assess the risks of it and put controls in place. Some tasks, like most confined space entries and much live electrical work, should not be done alone. The assessment is where you record that decision and the reasoning.
Does Gaffer track my lone workers live?
Gaffer records whether GPS tracking and a panic alarm have been provided as part of the assessment, and the live staff map shows where your team is during the working day. The assessment itself is the risk record, not the tracking device.
How often should these be reviewed?
Each assessment carries a review date you set. In practice they should be revisited when the work changes, the worker changes, or after any incident or near miss involving lone working.
Can one assessment cover several workers?
Assessments are recorded against a worker and an activity, because the individual risk factors — medical, experience, capability — are part of what you are assessing. For a team doing identical work you would copy the assessment per person rather than assess them as a group.