Having read all this thread and also read the brochure. I can confrim that ther is a charge of £100.00 for 170A's. This is a offical charge, so why would you pay the examiner directly? Sorry but this is not right, you should be invoiced, end of.
For an examiner/instructor to ask for payment in this way, with no reciept (if true) is wrong. If I was said person, I would be very worried about HMRC getting hold of this.
If I was a candiate I would ley HMRC and also the CAA know as I am sure both parties would be want to know.
Wonder if the person concerned kept records, paid Tax and VAT.