The people at the financial margins both top and bottom are where the varied compliance is to be found it's us suckers in the middle that are hog tied and abused.
Slackers - The personal allowance has been raised by £1000 though so this is actually better for lower income workers and is only a reduction of £1400 on the basic rate band in real terms (not £2400). If you aren't a higher rate tax payer you will actually be about £200 a year better off.http://www.hmrc.gov.uk/budget-updates/autumn-tax/tiin2525.pdfWhatever "casual payments" are, they've always been taxable as (despite widely held misconceptions) there's no such thing as "casual labour" when it comes to employment income.
Whatever shite they've sent you (they're good at that!) your personal allowance will be £7475. Everyone's is. This may then be adjusted for age / benefits in kind / expenses etc etc etc but this "casual payments" thing makes no sense whatsoever. You're right to check it out.