I guess my comment is subjective but to me a deposir of £50,000 or monthly income of £100,000 are substantial sums, esoexially compared to Standard Banks £5,000 requirement.
The likes of Natwest, HSBC, Lloyds etc require large sums to open maintain an offshore account. However Standard Bank offers an offshore account with a minimum of deposit of £5,000 - the lowest requirement i have seen so far.