Specialist in UK tax returns for UK resident/US domiciled individual

Wife of an existing client has been UK resident for the last 11 years, but is domiciled in the US.  She has considerable income (circa £500k pa, mainly capital) from a Trust in the US, and files US returns and pays Federal taxes.  She has never submitted a UK tax return.  This is not our usual area of work, and as the rules regarding non-domicile are so complex, would be grateful if anyone could recommend someone experienced in this field.