What about accepting both?
What if you accept service charge – can you then accept tips too? The short answer is yes, in fact, this is common. Some customers add money on top of the service charge, in which case the surplus is seen as a voluntary tip separate from the service charge.
To maximise the overall amount given for the service, you could choose to add a smaller-than-average service charge of, say, 10%. With such a “base” charge, customers may be more inclined to add a small tip in cash or by card. The total amount of the two is likely higher than if the customer only paid a voluntary tip.
Even if you don’t encourage tipping with a service charge, you still need a clear policy at the workplace in case employees receive gratuities separately. If a voluntary amount is added to a card payment, it is the employer’s responsibility to process this in accordance with HMRC and internal policies.