No wonder we Scots get a hard time for being tight with money!
The market decides if £200 per hour for her is too much.
Lets face it, if it was too much, she wouldn't be busy and she would have to reduce her price.
Therefore, the market (read we punters) has determined her rates are sustainable.
Whether any punter, or reader of this site considers it too much for them frankly is a statement of their willingness, or lack thereof, to pay £200 per hour.
If the girl is good, and by all accounts she seems to be pretty capable, then the rate is fair and reasonable.