I have often mentioned the National Insurance contribution (NIC) problems that can arise when a doctor has both a salaried position and freelance work. It applies mainly to locum GPs and consultants with private practice, but it can apply to partners with a salaried appointment too). Up until now you needed to apply for deferment of Class 4 NIC, so that you didn’t pay too much NIC in the first place and then have to get it back afterwards.
Historically, if you didn’t ask, you didn’t get it and we have managed to obtain some huge refunds (thousands of pounds) for some doctors who didn’t know about it.
In recent years the department are getting better at picking up those they think may have overpaid, although it is certainly not foolproof, and are writing to them to ask for further information to review the overall position.