Another domestic worker, this time working for diplomats from the Republic of Sudan as a cook in the kitchens of the embassy in London. Ms Benkharbouche claimed unfair dismissal and unlawful deductions from wages. Her colleague, Ms Janah, had more general duties and made those and other claims, including racial discrimination and harassment and breach of the Working Time Regulations 1998.

Both claimants lost their cases at tribunal but the UKEAT upheld the claims relating to working time and discrimination, ruling that the SIA should be disapplied for those claims - Article 47 of the EU Charter of Fundamental Rights enshrines the right to a fair trial and effective remedy in relation to EU rights. The Court of Appeal has agreed with the EAT on this. 

The Court of Appeal ruled that, "...an EU Charter right can be relied on “horizontally” in certain circumstances," that is it may be relied upon directly in claims between private parties in the national courts. 

Those claims based in domestic (non-EU) legislation are not protected i.e. the immunity of foreign states cannot be disapplied. The SIA is incompatible with the Charter and the Court proposed that it would make a declaration of incompatibility pursuant to section 4(2) of the Human Rights Act (a power not available to the employment tribunal or EAT). 
http://www.judiciary.gov.uk/wp-content/uploads/2015/02/benkharbouche-and-janah-v-embassy-republic-sudan-others.pdf