Clean rebuild of existing CakePHP ecommerce platform

PHP / CakePHP Developer Required – Clean Rebuild of Existing E-commerce Platform

I am looking for an experienced PHP / CakePHP developer to carry out a clean rebuild of an existing production e-commerce platform.

This is not a migration, upgrade, or patch-up of the current codebase.
The rebuild must use the current live site behaviour as the reference, with no reuse of existing application code beyond functional reference.

The priority is technical stability, correctness, and long-term maintainability, not visual redesign.

Project Overview

Clean rebuild using modern CakePHP (CakePHP 5 preferred)
Full behavioural parity with the current live site
No reuse of existing application code (reference only)
Fixed-price proposal with clearly defined milestones
Acceptance-based milestone payments (not time-based)

This is a real production e-commerce system with genuine operational complexity — not a simple storefront.

Core Functional Areas (non-exhaustive)

The rebuilt system must fully support:

Catalogue (categories, filters, variants, pricing)
Basket and checkout flows
Payment integration (Opayo / SagePay)
Orders, refunds, cancellations, exchanges
RMA workflows (returns, refunds, exchanges, stock reinsertion)
Admin functionality (orders, RMAs, products, reports, exports)
Email workflows (order, dispatch, refund, RMA status, system emails)
Stock movement, stock bases, and oversell prevention
Discount logic (product, category, promo codes, customer credits)
Shipping rules, cut-offs, blocked dates, and rate logic
Reporting, exports, and audit logging

Behaviour must match the live system exactly unless explicitly agreed otherwise.

Documentation Provided (Available Immediately)

The following documents are provided up front and form part of the project contract:

Full Functional Specification
System Scope Document
Developer Handover Pack

These documents define the required behaviour, scope boundaries, and acceptance criteria.
All proposals must be based on these documents, not assumptions or alternative interpretations.

What I’m Looking For

Strong CakePHP experience (framework internals, ORM, entities)
Experience building or rebuilding non-trivial e-commerce systems
Clear, structured communication
Realistic timelines
Comfort working to a written specification and acceptance criteria

What This Is Not

Not a quick fix or partial migration
Not a design-only project
Not suitable for junior developers
Not suitable for template-based or plugin-driven approaches

Budget

Target budget: £6,500 (fixed price)
Competitive proposals below this level will be considered where scope, delivery approach, and quality are not compromised
Lowest price is not the deciding factor

Proposal Requirements

Please include:

Relevant CakePHP and e-commerce experience
Brief description of your proposed architecture approach
Estimated timeline
Fixed price with milestone breakdown
Confirmation you can work to strict behavioural parity as defined in the attached documentation

Proposals that do not reference the documentation or address the above will not be considered.