Sticky Steering

[IRD]

My car is unfortunately one of those that suffers from this problem when the ambient temperature is high or when I've been using it for an hour or more. It is quite disconcerting when you are driving on a motorway. Looking back to what has been written by GuidoK and others last year it seems there is a fix by rotating the eccentric adjuster ring that sits between the electric motor and the steering rack.
I have very little technical expertise and if I tried to do this myself I know I would make a mess of it. Does any one know of reliable garage/ individual who could carry out the fix? I live near Lincoln but would be willing to travel to get this problem corrected. It really is spoiling my pleasure driving the car
Hoping someone can help.