@ timberman Hello sadly your doctor is right, you need to be in contact with an occupational therapist, and if you are in a trade union, their health and safety people.
The occu is one who assess your work fitness and job suitability, and the union people are there to look after your interests.
Get a copy of the report and if your gp, would give you some assistance in getting to the right person.
Have you had any condition issues while you have been at work and at height?
There are many things that can have you 'grounded' could even be they are just 'edgy' or has there been any issues in similar industrial situations, they are picking up on?
Maybe the web site has some information that might be of help to you, sorry I cannot be of more help to you, ttfn from Karen