I became an examiner in 1997. Just phoned the CAA, they checked their records, said thats ok, paid the fee and they sent back the forms and handbook.
Read the relavant parts in the handbook and conducted tests.
No problems.
I used my 20 years of flying and 10 years instructing to make my judgements.
I think 5000 hrs instructing should be a minimum.
So now i have to attend some seminar where i pay, to be told information that should come to me direct in paper form from the CAA.
Last seminar i went to just came away with a stinking cold and lost a total of 3 days income!