Working out yield with mortgage payments

Hi all

I have bought three different books and each give different way of working out yields and thus arrive at different figures so I thought i'd get the pro's opinion.

Purchase price inc redecorating..........£165k

deposit..................................£24k

fixed costs including below .............£3530
stamp duty
mortgage arrangement fee
mortgage broker fee
legal
survey

Tenant finding fee.......................£500

Annual rent
(achieved by similar properties).........£9600

repayment mortgage costs.................£683

obviously I don't expect you to work it out but what formula do you use... do you incorporate mortgage repayments

cheers