Tax codes for pension and second zero hours job.

My tax codes keep getting changed. I receive a pension and have a zero hours job. Pension was L code and zero hours job was DO - I'm happy with this as I get my allowances on my pension and pay 40% on the job income when I work. The codes keep being changed to something similar to Pension K code and and job BR. Means I pay additional tax on my pension whether I work or not. Is it possible to have the L code fixed on the pension and the job allocated DO permanently? I have to ring you guys up at least twice a year to sort this out. Seems illogical to have pension on a K code which may not be required if I don't work. Is it to with which income is allocated as the main one? Is there way to correct this?

Hi Grimbo_66,
To give you the best advice and confirm if we can update your codes as requested, we may require more information.
To allow us to review your record and advise you further, please contact us by webchat or phone via Income Tax: general enquiries
Thank you.