Further to a chat with support, I can withdraw up to 200 a month. If I withdraw 150 GBP I can then withdraw 50 Euro / 50 USD or visa versa or just 200 of any of those currencies. As long as the total is 200 regardless of the exchange rate.
But if I withdraw other than USD / GBP / Euro, then the limit is 200 in the my base currency. Is his correct @AndreasK ?