Our commission structure isn’t in our contract and when I reduced my hours I only had a letter confirming the reduced hours and no other amendments. The commission structure is worked out on a percentage i.e if you generate £10k income then you receive 10%. With the commission scheme being pro rata it means than I can get paid less for bringing in the same revenue as a full-time person. After discussing it with my line manager it was suggested that I could revert to the full-time commission structure which means that my target would not be reduced, I am .52 FTE so I would be expected to do the equivalent of a full-time person in half the time on half the salary. Is this fair?
The Part-Time Workers Regulations confirm that part-time workers should not be treated less favourably than full-time workers. This applies to contractual benefits, which should be given to part-time workers on a pro rata basis. The easiest example is holiday: where a full-time employee has 25 days holiday per year; a part-time employee working three days per week should get 15 days.
Arguably, applying a full-time commission structure of this type to part-time employees is treating them less favourably because they have less hours in which to meet the threshold. The simplest solution would be to pro rata the threshold, i.e. a 0.52FTE employee should have a threshold of £5,200.
I would suggest you make this point informally at first with your line manager and involve HR if necessary. It’s likely that no-one has considered the impact of the Part-Time Workers Regulations. If an informal approach is not successful, you should raise a grievance. Ultimately, you might need to consider an Employment Tribunal claim if you don’t get anywhere and are losing out on commission.