When is the ratio used in a rights issue to adjust for the bonus element of the rights?

Use Diluted EPS instead of earnigs per share and you will be using the correct ratio.  Here the full Equity Shares + any rights shared issued or where Shareholders have right to purchase such shares are considered in calculating the Earnings per share.

Each countries has it's own rules and regulation. Once we enter a certain location we should always follow their rules, we people who visit the place should adjust not the place will adjust for us. Yes we have our own rights but we should use it in the right way.