There is, and will continue to be, a requirement for Clinical Technologists in the NHS; supporting professional end users in some form or other. In my experience there are certain "value-added" benefits associated with in-house departments that take on a diverse range of roles and have a wealth of knowledge and expertise available.
Yes, it's likely that there will be less requirement for in-house repairs (and this is the case in my experience) but one certainty is that the quantity, hence capital cost, of equipment in the NHS will certainly continue to rise; relative to the overheads involved with running a technical support service in-house. So perhaps it is not as clear-cut as Alex suggests.
The risk associated with the use of equipment will continue to rise as will the requirements for the purchaser and employer and manufacturers to ensure that equipment functions correctly, is safe, that operators are trained in its use and it is being managed and supported technically speaking.
Therefore the argument is not whether there will be Technologists (I do not like the term "repairmen" it does not adequately describe our role) in the future but how many and what will their roles be. It's a shame that Alex does not enlighten us to his thinking on this aspect.
As for the term professionalism that Alex uses, inferring an association with Medical Physics exclusively, then in 3 years it's likely that whether you're a Medical Physics Technologist or a Medical Engineering Technologists you'll be regarded in the NHS scheme of things as a state-registered Professional; irrespective of job role, duities or responsibilities.
Whatever tasks and duties are required of individuals, whose roles are described under the umbrella Clinical Technologists, then my prediction is that many in-house departments will be providing a service in-house; whether they're employed as Medical Physics Technologists, Medical Engineering Technologists or third-party agents.