If you're someone who loves the intersection of LLM systems, experimentation, and realworld product impact, this is the kind of role where your work won't stay hidden. You'll see it live, in customerfacing journeys, SEO performance, personalisation, and in the quality of the content we publish.
And to be clear: this is not a role for someone who has only ever engineered prompts in isolation. You'll definitely write prompts - but the value here comes from understanding how LLMs behave in real systems, with real data, and knowing how to evaluate, measure, optimise and deploy them at scale. If you have the data science mindset and the LLM engineering skillset, this is where you can genuinely shape things.
What you'll actually be doing?
* Designing, testing, and optimising prompts and promptchains for production LLM applications
* Building evaluation frameworks to measure quality, safety, relevance, latency and cost
* Working with RAG architectures, embeddings and vector databases to improve retrieval and contextual accuracy
* Owning and developing our SEO contentoptimisation tool - improving product page copy for both relevance and discoverability
* Helping power personalised recommendations and messaging in our Personalisation squad
* Enhancing our Wellness Hub (our library of health articles and expert content) by generating, rewriting and improving pieces in safe, evidencebased ways
* Partnering with Data Engineering on context management, memory strategies, tool/functioncalling, observability and logging
* Monitoring and mitigating model drift, prompt degradation and system regressions
* Acting as a goto LLM expert across the business, helping teams understand what's possible and what's not
* Staying close to the evolving LLM landscape and translating new ideas into useful, practical improvements
How we'll see your impact
* Customers engage more with product pages because the content is more helpful and tailored
* SEO performance improves thanks to your optimisation tools
* We publish higherquality health content that's accurate, engaging and aligned with our brand
* Customers receive more relevant recommendations at the right moment
* Internal teams work faster thanks to stronger, more reliable LLMpowered tools
* Clear evaluation metrics guide smarter, datadriven AI adoption
* LLM capability across H&B grows because you've helped demystify the technology
The Person
What you'll need
* Handson experience developing LLM applications beyond just prompt writing
* Solid data science foundations: experimentation, evaluation, statistical thinking, working with realworld datasets
* Strong understanding of: prompt optimisation, RAG, embeddings, vector stores, context management and LLM evaluation
* Very strong Python skills - this is a genuinely handson role
* Ability to reason about tradeoffs between quality, latency and cost
* Experience with Git, version control and CI/CD
* Confidence translating complex LLM concepts for nontechnical colleagues
* Curiosity, pragmatism, and comfort shaping a firstofitskind role
Benefits
Wellbeing & Lifestyle Benefits
* 33 days holiday, including bank holidays
* Health Cash Plan
* Life Assurance
* Incentive scheme based on company & personal performance
* Virtual GP
* Private Medical care
* FREE at-home blood test kit
* Holiday Purchase option
* Pension Contribution scheme
* Access to Wellhub' with gyms, studios and wellbeing apps
Discounts & Savings
* 25% Colleague Discount with FREE Standard Delivery
* Exclusive Discounts from a wide range of partners
* £/50 Annual Product Allowance to spend in store
Learning & Development
* Access to a variety of learning opportunities, including Level 2-5 Apprenticeships, Workshops and our Digital Learning Library
* AND MORE!