We all struggle through busy periods but there are always people out there willing to help, and make a few extra pennies for a rainy day, or gain valuable experience for their future.
If you find yourself too busy to answer all your calls during a busy day, have you thought about approaching a local college or training organisation, who may have students needing a placement? You will both benefit from this, with you getting time to give your undivided attention to your fluffy clients and the student will gain valuable transferable skills (filing, answering calls, booking dogs in, brushing the floor, merchandising any retail stock, placing orders, making that cuppa to keep you going!)
Another option would be to take on a casual member of staff or offer a zero hour contract. You can check out the differences on the Labour Relations Agency website. You would have a member of staff that could help you out when required but you would not have to offer them hours over your quiet periods.
Remember to check out the rights and contracts of these employees.