If your total income is over £100,000 in 2014/15, then you will lose £1 of the personal allowance for every £2 of income over £100,000. As your income will be £113,333 (£30,000 + £75,000 + £8,333 tax credit), you will be left with £3,333 of your £10,000 personal allowance. The loss of £6,667 of your personal allowance will cost you £2,833 in tax.
The 20% tax band covers the first £31,865 of taxable income. Of that, £26,667 will be used by the taxable part of your salary (£30,000 - £3,333). The balance of £5,198 will cover the first £5,198 of your £83,333 dividend and that will be taxable at the lower dividend rate of 10% (£519.80). The balance of the dividend of £78,135 (£83,333 - £5,198) will be taxable at 32.5% (£25,393.88). The total tax liability on the dividend will, therefore, be £25,913.68. Deduct the 10% tax credit of £8,333.33 and you are left with a net liability on the dividend of £17,580.35. This will be payable on 31 January 2016.
I hope this helps but let me know if you have any further questions.