I'm Principal Architect for the Bank of England.  I see service design in the context of enterprise design, taking an architectural view.  My doctoral thesis, published in 2017, explores the concept of service architecture and how architecture evaluation techniques developed in the software domain can be applied to service design.  It contains a case study of the evaluation of competing service designs for a key stage of the asylum service at the UK Border Agency, which led to the development of the Service Architecture Review Method.