Harnham

Data Wrangler

⭐ - Featured Role | Apply direct with Data Freelance Hub
This role is for a Data Wrangler with a 3-month contract at £600 - £750 per day, hybrid in London. Key skills include strong SQL, Python (Pandas), and experience with large datasets. Prior work in regulated environments is preferred.
🌎 - Country
United Kingdom
💱 - Currency
£ GBP
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💰 - Day rate
Unknown
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🗓️ - Date
March 8, 2026
🕒 - Duration
3 to 6 months
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🏝️ - Location
Hybrid
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📄 - Contract
Inside IR35
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🔒 - Security
Unknown
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📍 - Location detailed
London
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🧠 - Skills detailed
#PostgreSQL #Code Reviews #Datasets #Oracle #XML (eXtensible Markup Language) #Pandas #SQL (Structured Query Language) #"ETL (Extract #Transform #Load)" #SQL Server #Python #Databases #Compliance
Role description
DATA WRANGLER 3-MONTHS £600 - £750 PER DAY - INSIDE IR35 HYBRID - LONDON This is an exciting opportunity for a highly analytical and detail-driven Data Wrangler to support a major forensic data analytics project. You'll be working with a specialist team to ingest, clean, and compare massive datasets from multiple complex systems - some sources containing hundreds of millions of records. The ideal candidate will thrive in ambiguity, work independently, and apply a forensic lens to messy, unstructured operational data.THE COMPANY You'll be working with a globally recognised advisory firm, known for its work in forensic investigations, compliance, and financial disputes. This team operates in a highly confidential environment, supporting projects with national-level visibility. You'll be joining a collaborative, focused, and expert-led group engaged on a high-stakes piece of work.THE ROLE You'll play a hands-on role working with data received from external clients-often incomplete, inconsistent, or raw. Your job is to wrangle that data into usable form, run forensic-level comparisons, and support reporting back to clients. You'll work in a secure VDI environment and must be comfortable navigating complex and sensitive data. Key responsibilities include: • Ingesting and transforming large datasets (100M+ rows), from Oracle, SQL Server, and flat files (CSV, XML). • Writing and reviewing SQL and Python (Pandas) scripts to clean and join data across multiple sources. • Conducting forensic comparisons between data sources (e.g., matching millions of XML records to transactional logs). • Supporting peer code reviews to ensure high quality and reduce rework. • Working within a locked-down environment using tools like VS Code, SQL clients, and secure remote desktop environments. • Collaborating with data consultants and forensic analysts to troubleshoot logic and ensure audit-quality outputs.KEY SKILLS & REQUIREMENTS • Strong SQL (T-SQL, Oracle, or PostgreSQL) - must be comfortable with complex joins and large volumes • Python with Pandas - mandatory for data transformation and wrangling • Experience working with large operational databases, text files, and legacy data sources • Strong attention to detail and a forensic mindset - ability to spot inconsistencies, gaps, and unusual data behaviour • Prior experience in a regulated, sensitive, or secure data environment is a big plus • Previous work in or alongside large consultancy firmsHOW TO APPLY Please register your interest by sending your CV via the apply link.