Job Description:

Principal Data Scientist (Fine-tuning & model optimisation) - AI Models Lead

Hybrid: Remote

Paying up to £130,000 + bens

Permanent

Experis are delighted to be partnering with a highly successful and growing software organisation as they invest heavily in building a cutting-edge AI capability at the heart of their product suite.

We are supporting them in the search for an AI Models Lead, a key foundational hire who will own the development, fine-tuning, and production delivery of domain-specific AI models within a large-scale programme.

This is a rare opportunity to join at an early stage and build a fine-tuning capability from first principles, shaping how AI models are developed, evaluated, and deployed in real-world, regulated environments. Looking for someone who has moved beyond prompt engineering and RAG into genuine model adaptation, evaluation, optimisation and fine-tuning.

What You'll Be Doing

• Designing and leading the end-to-end model fine-tuning strategy, such as SFT, LoRA / QLoRA, and optimisation approaches
• Selecting and evaluating base models (e.g. Mistral, Qwen, Phi, Falcon) based on performance, cost, and use case
• Defining evaluation frameworks and standards to ensure models meet production-grade quality and reliability
• Building and scaling a suite of fine-tuned models to support multiple product use cases
• Owning experiment design and reproducibility, including tracking, benchmarking, and iteration cycles
• Working closely with data, domain and product teams to translate real-world requirements into model behaviour
• Leading, mentoring, and growing a team of ML Engineers while remaining hands-on technically
• Driving models through to production environments, ensuring robustness, scalability, and performance

Experience Required

• Proven experience fine-tuning machine learning / LLM models in production environments
• Strong track record of deploying AI models at scale and understanding real-world failure modes
• Hands-on experience with Generative AI / LLM architectures and frameworks
• Strong Python engineering capability and familiarity with ML tooling (e.g. HuggingFace, PEFT, TRL, W&B)
• Experience working in cloud environments (AWS preferred)
• Ability to operate as a player-coach, combining deep technical expertise with leadership
• Pragmatic mindset, comfortable working in ambiguous, evolving environments
• Excellent communication skills, with the ability to engage senior stakeholders and influence direction

Why Join

• Opportunity to build and shape a core AI capability from the ground up
• Work on real-world AI use cases where accuracy and trust genuinely matter
• Highly visible role with direct exposure to senior leadership and strategic initiatives
• Join a business making significant long-term investment in AI-driven innovation

If you're interested in learning more, please reach out to Jacob Ferdinand at

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