The Architects Registration Board is the independent UK regulator for architects. They keep the official register of UK architects and deal with complaints and any misuse of the term ‘architect’
Architect is a protected title and thus only those on the register can use the term. Architectural designers, technicians etc are parallel positions, but have not completed the same training or have the same code of conduct to abide by. The ARB pursue individuals or firms using the title that are not on the register, but they rely on members of the public notifying them on this.
Should you have an issue with an architect you can take this up with the ARB who will look into it, and if necessary take punitive action, or suspension from the register.
You can search the register here: http://architects-register.org.uk/
Their website has useful information on what to expect from an architect, guides and also the roles that they undertake.