Anyone who really is an architect will have to be registered with the above, http://www.arb.org.uk
Most of us are chartered members of the RIBA, the only professional chartered body of the profession.
We are, 'on top of that' an RIBA Chartered Practice which means even more independent protection for you commissioning a building design and 'on top of that' we are the only building design profession that requires us all to have University backed qualifications, training, skills, knowledge and experience over a minimum of seven years to above Masters Degree level.
'On top of all that' KR.eativ: Architects is also:
Therefore anyone else offering 'architectural services' will not be an architect and have very little knowledge of architecture, or could even be an architect who has been 'struck off' the register for negligence, unprofessional behaviour or a crime (which does happen). The reason for that is the fact that to use the the term 'architectural' in your job title/description or the word 'architecture in your business name does not require any qualifications or ability whatsoever.
Some such service providers may be OK for you but ask yourself why they are not architects. It may be that they are just too lazy to bother, as they can make money without having to independently prove their ability. Sad, but that is the law.
There are 'related' building design professionals such as Chartered Engineers, Chartered Surveyors and Chartered Technologists but they are not architects and do not have the same skillsets, knowledge, education, qualifications and training etc.
So when someone introduces you to an architect please ensure that the person/business they are promoting is actually an architect as it could be a very expensive mistake. Just think of all the recent press about bad housing, very little of it has been designed by an architect but by 'designers', town planners, Council officers and Councillors etc. A well designed building (as stated in a report prepared for The Modern House agency) can add 10% to 12% more to the value of a completed building than a badly designed one designed by a non-architect. A fact that has the effect that commissioning an architect can save you money by costing less than the value we add to the build environment.
To be honest, the above is a bit of a rant as I am fed up with conservations and phone calls that begin "my architect has given us a bad service". When I ask "who was that" they reply with a name of a person or business that is most definitely not an architect. The media is blame too as all sorts of crimes are reported as being by 'an architect' when in actual fact they rarely are not and never were architects (yet more 'fake news').
The positive thing to take away from the above is that real architects, when allowed to be their professional selves, are the only people fully architecturally qualified to provide you, the client, with a building that suits your needs and requirements. We do this, for larger buildings, by leading a design team of fellow chartered professionals to design and convey the relevant construction information to the contractor.