Most taxpayers born before 6 April 1948 are entitled to a higher Personal Allowance known as an age-related Personal Allowance. The amount depends on their date of birth and their income. The income limit for age-related Personal Allowance is £27,000 in the 2015/2016 tax year.If income is above this income limit, the age-related allowance is reduced by £1 for every £2 of income over the limit.he amount depends on their date of birth and their income. The income limit for age-related Personal Allowance is £27,000 in the 2015/2016 tax year. If income is above this income limit, the age-related allowance is reduced by £1 for every £2 of income over the limit.