I'm clearly doing something wrong but my client doesn't have a nominal code for accountancy fees and I can't seem to add one?

Hello Trish31, 

Welcome to the Community page, 

You should be able to create most types of accounts, there are some that only one type can be created, if its one of those then you can look through the charts of accounts looking at the type and detail type to find the account and if necessary you can rename it as well.