Thanks Lamb Chop
I presume the CAA response is specific to peanut allergy as opposed to other allergies, but I can't help thinking this is rather clutching at straws. An allergist can certainly help determine if there is an allergy or not. In hospital practice perhaps 70% of so called allergies don't exist - either a misunderstanding of what constitutes an allergy or poor association.
What will be more difficult for the allergist is to determine the severity. There are a number of fairly recent papers showing this cant be done. Importantly the risk is the initial allergic response - peanut based drugs are used in surgery and one of the most dangerous situations we can face, but there is evidence that subsequent responses are milder.
The consensus is that proper training in avoidance and the use of for example inhaled epinephrine can provide safety. A paper earlier this year from Cambridge also demonstrated effective desensitisation in a small group and you should certainly discuss this before being labelled at Gatwick.
Bottom line - choose your allergist carefully, investigate the latest research, and ask to see the report before it is sent. A five minute consultation and one line report from a busy NHS clinic is not what you want. Proper discussion with your allergist or referral to a centre interested specifically in peanuts BEFORE the CAA get involved would be the route I would go.