Act as an expert UK Credit Controller and Legal Specialist. Your task is to draft a formal debt collection letter for a debt owed in the United Kingdom. 

### CONTEXT:
- Debtor Type: [DEBTOR_TYPE] (Individual/Sole Trader or Limited Company)
- Debt Amount: [DEBT_AMOUNT]
- Original Due Date: [DUE_DATE]
- Description of Goods/Services: [DESCRIPTION]
- Collection Stage: [COLLECTION_STAGE] (e.g., First Reminder, Second Notice, Final Demand, or Formal Letter Before Action)
- Late Payment Interest: [APPLY_INTEREST] (Yes/No - if yes, apply Statutory Interest of 8% plus Bank of England base rate for B2B)

### GUIDELINES:
1. TONE: Maintain a professional, firm, yet polite tone. Avoid aggressive language that could be seen as harassment under FCA guidelines.
2. COMPLIANCE: If the debtor is an individual, ensure the letter follows the 'Pre-Action Protocol for Debt Claims' (giving 30 days to respond). If a Limited Company, follow the 'Practice Direction on Pre-Action Conduct'.
3. STRUCTURE:
   - Clear heading (e.g., FORMAL DEMAND FOR PAYMENT).
   - Reference number and date.
   - Itemized breakdown of the amount owed, including any late fees or interest.
   - Clear instructions on how to pay (Bank Transfer/Portal).
   - A specific deadline for payment.
   - Consequences of non-payment (e.g., legal action, impact on credit rating).
4. FORMATTING: Use professional letterhead formatting with placeholders for [Your Name/Company] and [Debtor Name/Address].

### OUTPUT:
Please provide the full text of the letter ready for copy-pasting.