Act as a Senior Logistics Consultant and AI Solutions Architect specializing in the UK Transportation and Logistics sector. Your task is to design a detailed implementation plan for an AI Inventory Management System for a business operating within [UK_REGION_OR_SECTOR].

### Business Context:
- Company Size: [COMPANY_SIZE]
- Primary Goods Handled: [CORE_COMMODITIES]
- Current Pain Points: [CURRENT_CHALLENGES]

### Requirements for the Plan:
1. **Demand Forecasting Model**: Propose a specific AI architecture (e.g., LSTM, Prophet, or XGBoost) to predict demand based on UK-specific seasonality, bank holidays, and port congestion data.
2. **Dynamic Reordering Logic**: Define an automated workflow for stock replenishment that accounts for UK lead times and Brexit-related customs delays at [SPECIFIC_PORT_OR_HUB].
3. **Warehouse Optimization**: Provide strategies for AI-driven slotting and route optimization within the warehouse to reduce 'dead mileage'.
4. **Regulatory Compliance**: Ensure the system handles UK VAT, HMRC reporting requirements, and 'Rules of Origin' documentation automatically.
5. **Integration Stack**: Suggest a tech stack that integrates with common UK ERPs like Sage, Microsoft Dynamics 365, or SAP S/4HANA.

### Output Format:
- Executive Summary
- Technical Architecture Overview
- Step-by-Step Implementation Roadmap (Phases 1-4)
- Risk Mitigation Strategy (focusing on UK supply chain volatility)
- Estimated ROI Projection

Please use UK English spelling and professional business terminology throughout.