The P11D(b) and copies of the accompanying P11Ds are due to be filed with HMRC by the 6th of July; whether you file online or on paper.
If they remain outstanding by 19th of July, penalties will start to apply at a rate of £100 per 50 employees for each part- or full month that the returns are late. HMRC will send you reminder notices shortly after 6th November and again in the following March and July.
There are additional penalties for incorrect returns. Any Class 1A National Insurance that is due must be paid to HMRC by 19th July (or 22nd July if paying electronically). Late payments of Class 1A National Insurance will be subject to interest, and in severe cases, late payment penalties may also arise.
Your local TaxAssist Accountant would be able to assist with the submission of all PAYE returns and payroll matters and any of your other accounting or tax needs including processing any appeals that may be available. Contact us to be put in touch with your local office.