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Multi-disciplinary tax and compliance experience 

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James graduated from the London School of Economics with an honours degree in law in 2003 and is a fellow of the Association of Taxation Technicians and is a member of the Society of Trust and Estate Practitioners or STEP.

After he completed his legal practical training, his interest in tax led him to take up a position at KPMG as a tax advisor in the private client team in London. For two years James worked with high net worth and ultra high net worth individuals, and assisted them with tax advice and preparing their tax returns.

From KPMG, James moved to train as a solicitor whereupon qualification he took up a position at Withers LLP to practise as a private client solicitor in the international section of the Wealth Planning department between 2008 - 2015.

Highlights of James' time at Withers include the following:


  • Frequent provision of tax technical memoranda for clients (predominantly non domiciled individuals) on various areas of tax law.  Examples include, the Annual Tax on Enveloped Developments (‘ATED’) rules, the Statutory Residence Test (‘SRT’), the UK anti-avoidance rules (Section 720 and section 731 Income Tax Act 2007), and pre-arrival structuring for individuals coming to live in the UK.​


  • Numerous Liechtenstein Disclosure Facility ('LDF') disclosures (this disclosure programme has now closed and recently been replaced by the Worldwide Disclosure Facility).


  • Advising high profile clients in respect of their disputes with HMRC. This role involved mediations with HMRC, hearings at the First Tier Tax Tribunal, the Upper Tribunal and Judicial Review proceedings in the Administrative Court.


  • Working  on a number of Private Trust Company ('PTC') structures. One in particular encompassed numerous jurisdictions including, the Bahamas, the Cayman Islands, Delaware and Jersey.  The structure had elements of classic common law trusts together with structures more commonly associated with civil jurisdictions such as usufructs.​


  • Being named in eprivateclient’s list of top 35 under 35 private client practitioners.

James then went on to lead the UK tax team at an accountancy practice focussing on the media and entertainment industry.

In December 2017, James set up Auxilium Tax with a vision for providing clients with the best advice available from a combined legal and accounting background.


Sylwia has over 7 years experience of leading, managing and development of a tax compliance team. She advises individuals and owner managed businesses on complex tax issues with a strong emphasis on incorporating international tax aspects into UK tax compliance and planning. 

Her areas of expertise include:

  • UK taxation for both UK and non-UK domiciled individuals;

  • Regularisation of historic tax liabilities, HMRC disclosures facilities, simple and complex compliance checks;

  • Residence and non-residence issues (advising arrivers to and leavers from the UK); remittance basis planning;

  • OMB and SME tax compliance;

  • Offshore tax planning and non-resident trusts for resident non-UK domiciled individuals;

  • Planning for minimising foreign income and social security tax liabilities and withholding as well as maximising foreign tax credits;

  • Private Client Tax Services, Income Tax, Capital Gains Tax, Tax Return Compliance, Remuneration planning.

Education and Career

  • Sylwia studied Accounting and Finance at London Metropolitan University.

  • She trained and qualified as a chartered tax advisor and chartered certified accountant at a boutique accounting firm managing a portfolio of high profile media and entertainment clients.

Professional Memberships

  • Sylwia is a member of the Chartered Institute of Taxation.

  • She is a member of the Association of Chartered Certified Accountants


  • eprivate client top 35 under 35 2018​

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