The recognised standard: a Core of Knowledge laser safety certificate plus an Ofqual-regulated Level 4 laser/IPL qualification (e.g. VTCT Level 4 Certificate in Laser & IPL Treatments), with entry via Level 3 beauty or a healthcare registration. Local authorities (notably London boroughs) may also require premises licensing. Insurers increasingly insist on the regulated qualification.
Laser competence has three layers, and confusion between them powers a lot of poor training. First is the Core of Knowledge, the safety theory everyone operating Class 3B/4 devices needs. Second is the treatment qualification, the regulated Level 4 covering actual hair-removal and rejuvenation competence with assessed cases. Third is device-specific training on the machine you’ll fire. A Level 4 programme should package the first two with published clinic structure, and the third is a question to put to whoever sells you a machine.